diff --git a/soh/include/seqcmd.h b/soh/include/seqcmd.h
new file mode 100644
index 0000000000..53fce27bfb
--- /dev/null
+++ b/soh/include/seqcmd.h
@@ -0,0 +1,512 @@
+#ifndef SEQCMD_H
+#define SEQCMD_H
+
+#include "sequence.h"
+
+// ==== Primary commands ====
+
+#define SEQCMD_OP_MASK 0xF0000000
+
+typedef enum SeqCmdOp {
+    /* 0x0 */ SEQCMD_OP_PLAY_SEQUENCE,
+    /* 0x1 */ SEQCMD_OP_STOP_SEQUENCE,
+    /* 0x2 */ SEQCMD_OP_QUEUE_SEQUENCE,
+    /* 0x3 */ SEQCMD_OP_UNQUEUE_SEQUENCE,
+    /* 0x4 */ SEQCMD_OP_SET_SEQPLAYER_VOLUME,
+    /* 0x5 */ SEQCMD_OP_SET_SEQPLAYER_FREQ,
+    /* 0x6 */ SEQCMD_OP_SET_CHANNEL_VOLUME,
+    /* 0x7 */ SEQCMD_OP_SET_SEQPLAYER_IO,
+    /* 0x8 */ SEQCMD_OP_SET_CHANNEL_IO,
+    /* 0x9 */ SEQCMD_OP_SET_CHANNEL_IO_DISABLE_MASK,
+    /* 0xA */ SEQCMD_OP_SET_CHANNEL_DISABLE_MASK,
+    /* 0xB */ SEQCMD_OP_TEMPO_CMD,
+    /* 0xC */ SEQCMD_OP_SETUP_CMD,
+    /* 0xD */ SEQCMD_OP_SET_CHANNEL_FREQ,
+    /* 0xE */ SEQCMD_OP_GLOBAL_CMD,
+    /* 0xF */ SEQCMD_OP_RESET_AUDIO_HEAP
+} SeqCmdOp;
+
+// ==== Secondary commands ====
+
+// Subset of `SEQCMD_OP_TEMPO_CMD`
+typedef enum SeqCmdTempoCmdOp {
+    /* 0x0 */ SEQCMD_SUB_OP_TEMPO_SET,
+    /* 0x1 */ SEQCMD_SUB_OP_TEMPO_SPEED_UP,
+    /* 0x2 */ SEQCMD_SUB_OP_TEMPO_SLOW_DOWN,
+    /* 0x3 */ SEQCMD_SUB_OP_TEMPO_SCALE,
+    /* 0x4 */ SEQCMD_SUB_OP_TEMPO_RESET
+} SeqCmdTempoCmdOp;
+
+// Subset of `SEQCMD_OP_SETUP_CMD`
+typedef enum SeqCmdSetupCmdOp {
+    /* 0x0 */ SEQCMD_SUB_OP_SETUP_RESTORE_SEQPLAYER_VOLUME,
+    /* 0x1 */ SEQCMD_SUB_OP_SETUP_SEQ_UNQUEUE,
+    /* 0x2 */ SEQCMD_SUB_OP_SETUP_RESTART_SEQ,
+    /* 0x3 */ SEQCMD_SUB_OP_SETUP_TEMPO_SCALE,
+    /* 0x4 */ SEQCMD_SUB_OP_SETUP_TEMPO_RESET,
+    /* 0x5 */ SEQCMD_SUB_OP_SETUP_PLAY_SEQ,
+    /* 0x6 */ SEQCMD_SUB_OP_SETUP_SET_FADE_TIMER,
+    /* 0x7 */ SEQCMD_SUB_OP_SETUP_RESTORE_SEQPLAYER_VOLUME_IF_QUEUED,
+    /* 0x8 */ SEQCMD_SUB_OP_SETUP_RESTORE_SEQPLAYER_VOLUME_WITH_SCALE_INDEX,
+    /* 0x9 */ SEQCMD_SUB_OP_SETUP_SET_CHANNEL_DISABLE_MASK,
+    /* 0xA */ SEQCMD_SUB_OP_SETUP_SET_SEQPLAYER_FREQ,
+    /* 0xE */ SEQCMD_SUB_OP_SETUP_POP_PERSISTENT_CACHE = 0xE,
+    /* 0xF */ SEQCMD_SUB_OP_SETUP_RESET_SETUP_CMDS
+} SeqCmdSetupCmdOp;
+
+// Subset of `SEQCMD_OP_GLOBAL_CMD`
+typedef enum SeqCmdSubCmdOp {
+    /* 0x0 */ SEQCMD_SUB_OP_GLOBAL_SET_SOUND_OUTPUT_MODE,
+    /* 0x1 */ SEQCMD_SUB_OP_GLOBAL_DISABLE_NEW_SEQUENCES
+} SeqCmdSubCmdOp;
+
+// ==== Audio Sequence Primary Commands ====
+
+/**
+ * Play a sequence on a given seqPlayer
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to play the sequence
+ * @param fadeInDuration effect will depend on seqArg. See below
+ * @param seqArg no effect: < 0x7F, skip ahead: = 0x7F, will not play: >= 0x80 (see note)
+ * @param seqId the id of the sequence to play, see `SeqId`
+ *
+ * @note seqArg will also be stored in gActiveSeqs.seqId, any check against that seqId must also include seqArg.
+ * seqArg < 0x7F: fade in the sequence over `fadeInDuration` in units of (1/30th) seconds
+ * seqArg = 0x7F: start the sequence immediately, but begins `fadeInDuration` number of second into the sequence.
+ * seqArg >= 0x80: no sequence will play. Intended to load a soundFont asynchronously but was only half implemented
+ *                 (inferred from MM).
+ */
+#define SEQCMD_PLAY_SEQUENCE(seqPlayerIndex, fadeInDuration, seqArg, seqId)                                           \
+    Audio_QueueSeqCmd((SEQCMD_OP_PLAY_SEQUENCE << 28) | ((u8)(seqPlayerIndex) << 24) | ((u8)(fadeInDuration) << 16) | \
+                      ((u8)(seqArg) << 8) | (u16)(seqId))
+
+/**
+ * Stop a sequence on a given seqPlayer
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to stop the sequence
+ * @param fadeOutDuration duration the sequence will fade out over
+ *
+ * @note the 0xFF in the command is not read from at all, but is common in all Stop SeqPlayer Commands
+ */
+#define SEQCMD_STOP_SEQUENCE(seqPlayerIndex, fadeOutDuration)                                 \
+    Audio_QueueSeqCmd((SEQCMD_OP_STOP_SEQUENCE << 28) | 0xFF | ((u8)(seqPlayerIndex) << 24) | \
+                      ((u8)(fadeOutDuration) << 16))
+
+/**
+ * Add a sequence to a queue of sequences associated with a given seqPlayer.
+ * If the sequence is first in queue, play the sequence
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to queue the sequence
+ * @param fadeInDuration if the sequence is played, duration the sequence will fade in over
+ * @param priority priority in the queue. The highest valued priority will be queued to play first. Also used as `seqArg`.
+ * @param seqId the id of the sequence to play, see `SeqId`
+ *
+ * @note for the next sequence in the queue to play, the current sequence must be unqueued with the unqueue command
+ * @note for a priority >= 0x7F, similar effects happen as `seqArg` in the play sequence command
+ */
+#define SEQCMD_QUEUE_SEQUENCE(seqPlayerIndex, fadeInDuration, priority, seqId)                                         \
+    Audio_QueueSeqCmd((SEQCMD_OP_QUEUE_SEQUENCE << 28) | ((u8)(seqPlayerIndex) << 24) | ((u8)(fadeInDuration) << 16) | \
+                      ((u8)(priority) << 8) | (u8)(seqId))
+
+/**
+ * Remove a sequence from a queue of sequences associated with a given seqPlayer.
+ * If the sequence is first in queue, stop the sequence, and play the next one in queue if any
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to queue the sequence
+ * @param fadeInDuration if the sequence is stopped, duration the sequence will fade out over, and duration the next seq will fade in over
+ * @param seqId the id of the sequence to remove, see `SeqId`
+ *
+ * @note for the next sequence in the queue to play, the current sequence must be unqueued with this command
+ */
+#define SEQCMD_UNQUEUE_SEQUENCE(seqPlayerIndex, fadeOutInDuration, seqId)                 \
+    Audio_QueueSeqCmd((SEQCMD_OP_UNQUEUE_SEQUENCE << 28) | ((u8)(seqPlayerIndex) << 24) | \
+                      ((u8)(fadeOutInDuration) << 16) | (seqId))
+
+/**
+ * Set the volume of an entire sequence on a given seqPlayer. Fade to the volume over a specified duration
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to modify
+ * @param duration duration to transition to the volume
+ * @param volume the target volume for the sequence. Ranged from 0-0xFF, with 0x7F mapping to 1.0f
+ */
+#define SEQCMD_SET_SEQPLAYER_VOLUME(seqPlayerIndex, duration, volume)                                              \
+    Audio_QueueSeqCmd((SEQCMD_OP_SET_SEQPLAYER_VOLUME << 28) | ((u8)(seqPlayerIndex) << 24) | ((duration) << 16) | \
+                      (volume))
+
+/**
+ * Scale the frequency of every channel on a given seqPlayer over a specified duration.
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to modify
+ * @param duration duration to transition to the frequency
+ * @param freqScale the scaling factor to shift the pitch. Ranged from 0-0xFFFF, with 1000 mapping to 1.0f
+ *
+ * @note 2000 will double the frequency (raise an octave), 500 will halve the frequency (lower an octave).
+ *       Cannot be used with `SEQCMD_SET_CHANNEL_FREQ` as they will overwrite one another.
+ */
+#define SEQCMD_SET_SEQPLAYER_FREQ(seqPlayerIndex, duration, freqScale)                                           \
+    Audio_QueueSeqCmd((SEQCMD_OP_SET_SEQPLAYER_FREQ << 28) | ((u8)(seqPlayerIndex) << 24) | ((duration) << 16) | \
+                      (freqScale))
+
+/**
+ * Scale the frequency of a specific channel on a given seqPlayer over a specified duration
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to modify
+ * @param channelIndex the index of the channel to modify
+ * @param duration duration to transition to the frequency
+ * @param freqScale the scaling factor to shift the pitch. Ranged from 0-0xFFF, with 1000 mapping to 1.0f
+ *
+ * @note a frequency of 2000 will double the frequency (raise an octave), 500 will halve the frequency (lower an octave).
+ *       Cannot be used with `SEQCMD_SET_SEQPLAYER_FREQ` as they will overwrite one another.
+ */
+#define SEQCMD_SET_CHANNEL_FREQ(seqPlayerIndex, channelIndex, duration, freqScale)                             \
+    Audio_QueueSeqCmd((SEQCMD_OP_SET_CHANNEL_FREQ << 28) | ((u8)(seqPlayerIndex) << 24) | ((duration) << 16) | \
+                      ((channelIndex) << 12) | (freqScale))
+
+/**
+ * Set the volume of a specific channel on a given seqPlayer. Fade to the volume over a specified duration
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to modify
+ * @param channelIndex the index of the channel to modify
+ * @param duration duration to transition to the volume
+ * @param volume the target volume for the sequence. Ranged from 0-0xFF, with 0x7F mapping to 1.0f
+ */
+#define SEQCMD_SET_CHANNEL_VOLUME(seqPlayerIndex, channelIndex, duration, volume)                                    \
+    Audio_QueueSeqCmd((SEQCMD_OP_SET_CHANNEL_VOLUME << 28) | ((u8)(seqPlayerIndex) << 24) | ((u8)(duration) << 16) | \
+                      ((u8)(channelIndex) << 8) | ((u8)volume))
+
+/**
+ * Write a value that can be read as input directly by the sequence itself. This will be set to the global
+ * ioPort, which can affect the entire sequence.
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to write the input to
+ * @param ioPort the index of the array to store the input-output value
+ * @param ioData the value s8 that's written to the input-output array
+ *
+ * @note Each seqPlayer has 8 global ioPorts indexed 0-7.
+ * ioPort 0 and 1 are read-only-once, and will reset after being read by the sequence.
+ * ioPort 2-7 can be read multiple times.
+ */
+#define SEQCMD_SET_SEQPLAYER_IO(seqPlayerIndex, ioPort, ioData)                                                  \
+    Audio_QueueSeqCmd((SEQCMD_OP_SET_SEQPLAYER_IO << 28) | ((u8)(seqPlayerIndex) << 24) | ((u8)(ioPort) << 16) | \
+                      (u8)(ioData))
+
+/**
+ * Write a value that can be read as input directly by the sequence itself. This will be set to the channel
+ * ioPort, which will only affect a single channel.
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to write the input to
+ * @param channelIndex the index of the channel to write the input to
+ * @param ioPort the index of the array to store the input-output value
+ * @param ioData the value s8 that's written to the input-output array
+ *
+ * @note Each channel has 8 channel ioPorts indexed 0-7.
+ * ioPort 0 and 1 are read-only-once, and will reset after being read by the sequence.
+ * ioPort 2-7 can be read multiple times.
+ */
+#define SEQCMD_SET_CHANNEL_IO(seqPlayerIndex, channelIndex, ioPort, ioData)                                    \
+    Audio_QueueSeqCmd((SEQCMD_OP_SET_CHANNEL_IO << 28) | ((u8)(seqPlayerIndex) << 24) | ((u8)(ioPort) << 16) | \
+                      ((u8)(channelIndex) << 8) | (u8)(ioData))
+
+/**
+ * Disable (or reenable) specific channels from receiving input set by `SEQCMD_SET_CHANNEL_IO`
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to modify
+ * @param channelMask a 16 bit mask where each bit maps to a channel. Bitflag on to disable
+ *
+ * @note using AUDIOCMD_CHANNEL_SET_IO will bypass this channelMask
+ */
+#define SEQCMD_SET_CHANNEL_IO_DISABLE_MASK(seqPlayerIndex, channelMask) \
+    Audio_QueueSeqCmd((SEQCMD_OP_SET_CHANNEL_IO_DISABLE_MASK << 28) | ((u8)(seqPlayerIndex) << 24) | (u16)(channelMask))
+
+/**
+ * Disable (or reenable) specific channels
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to modify
+ * @param channelMask a 16 bit mask where each bit maps to a channel. Bitflag on to disable
+ */
+#define SEQCMD_SET_CHANNEL_DISABLE_MASK(seqPlayerIndex, channelMask) \
+    Audio_QueueSeqCmd((SEQCMD_OP_SET_CHANNEL_DISABLE_MASK << 28) | ((u8)(seqPlayerIndex) << 24) | (u16)(channelMask))
+
+// ==== Audio Sequence Tempo Commands ====
+
+/**
+ * Set the absolute tempo of a sequence on a given seqPlayer, fading over a specified duration
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to modify
+ * @param duration duration to transition to the tempo
+ * @param tempoTarget the target tempo for the sequence
+ *
+ * @note the absolute tempo is constrained to a maximum of 300
+ */
+#define SEQCMD_SET_TEMPO(seqPlayerIndex, duration, tempoTarget)                                                      \
+    Audio_QueueSeqCmd((SEQCMD_OP_TEMPO_CMD << 28) | (SEQCMD_SUB_OP_TEMPO_SET << 12) | ((u8)(seqPlayerIndex) << 24) | \
+                      ((u8)(duration) << 16) | (u16)(tempoTarget))
+
+/**
+ * Increase the tempo of a sequence by a relative value on a given seqPlayer over a specified duration
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to modify
+ * @param duration duration to transition to the tempo
+ * @param tempoIncrease the change to add to the current tempo
+ *
+ * @note the absolute tempo is constrained to a maximum of 300
+ */
+#define SEQCMD_SPEED_UP_TEMPO(seqPlayerIndex, duration, tempoIncrease)                     \
+    Audio_QueueSeqCmd((SEQCMD_OP_TEMPO_CMD << 28) | (SEQCMD_SUB_OP_TEMPO_SPEED_UP << 12) | \
+                      ((u8)(seqPlayerIndex) << 24) | ((u8)(duration) << 16) | (u16)(tempoIncrease))
+
+/**
+ * Decrease the tempo of a sequence by a relative value on a given seqPlayer over a specified duration
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to modify
+ * @param duration duration to transition to the tempo
+ * @param tempoDecrease the change to subtract to the current tempo
+ *
+ * @note the absolute tempo is constrained to a maximum of 300
+ */
+#define SEQCMD_SLOW_DOWN_TEMPO(seqPlayerIndex, duration, tempoDecrease)                     \
+    Audio_QueueSeqCmd((SEQCMD_OP_TEMPO_CMD << 28) | (SEQCMD_SUB_OP_TEMPO_SLOW_DOWN << 12) | \
+                      ((u8)(seqPlayerIndex) << 24) | ((u8)(duration) << 16) | (u16)(tempoDecrease))
+
+/**
+ * Scale the tempo of a sequence by a multiplicative value on a given seqPlayer over a specified duration
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to modify
+ * @param duration duration to transition to the tempo
+ * @param tempoScale the scaling factor of the tempo, relative to 100
+ *
+ * @note a tempoScale of 200 will go double-time, 50 will go half-time.
+ * the absolute tempo is constrained to a maximum of 300
+ */
+#define SEQCMD_SCALE_TEMPO(seqPlayerIndex, duration, tempoScale)                                                       \
+    Audio_QueueSeqCmd((SEQCMD_OP_TEMPO_CMD << 28) | (SEQCMD_SUB_OP_TEMPO_SCALE << 12) | ((u8)(seqPlayerIndex) << 24) | \
+                      ((u8)(duration) << 16) | (u16)(tempoScale))
+
+/**
+ * Reset the tempo of a sequence to the original tempo on a given seqPlayer over a specified duration
+ *
+ * @param seqPlayerIndex the index of the seqPlayer to modify
+ * @param duration duration to transition to the tempo
+ */
+#define SEQCMD_RESET_TEMPO(seqPlayerIndex, duration)                                                                   \
+    Audio_QueueSeqCmd((SEQCMD_OP_TEMPO_CMD << 28) | (SEQCMD_SUB_OP_TEMPO_RESET << 12) | ((u8)(seqPlayerIndex) << 24) | \
+                      ((u8)(duration) << 16))
+
+/**
+ * ==== Audio Sequence Setup Commands ====
+ *
+ * The setup commands are designed to wait to be executed.
+ * Up to 8 commands can be queued per `seqPlayerIndex`.
+ * These commands will only execute once that `seqPlayerIndex` is finished playing and is no longer enabled.
+ * They will often target a different player (`targetSeqPlayerIndex`) but not always.
+ */
+
+/**
+ * Setup a request to restore a volume on target seqPlayer once a setup seqPlayer is finished playing and disabled
+ *
+ * @param setupSeqPlayerIndex the index of the seqPlayer to wait for to be disabled
+ * @param targetSeqPlayerIndex the index of the seqPlayer to modify
+ * @param duration duration to transition to the volume
+ */
+#define SEQCMD_SETUP_RESTORE_SEQPLAYER_VOLUME(setupSeqPlayerIndex, targetSeqPlayerIndex, duration)         \
+    Audio_QueueSeqCmd((SEQCMD_OP_SETUP_CMD << 28) | (SEQCMD_SUB_OP_SETUP_RESTORE_SEQPLAYER_VOLUME << 20) | \
+                      ((u8)(setupSeqPlayerIndex) << 24) | ((u8)(targetSeqPlayerIndex) << 16) | (u8)(duration))
+
+/**
+ * Setup a request to unqueue a seqPlayer once that same setup seqPlayer is finished playing and disabled
+ *
+ * @param setupSeqPlayerIndex the index of the seqPlayer to unqueue once the same seqPlayer is disabled
+ *
+ * @bug this command was misimplemented and fails to unqueue. The command relies on `gActiveSeqs.seqId` for
+ * unqueueing, but seqId is reset before being used to unqueue. A simple fix is to unqueue based on
+ * `gActiveSeqs.prevSeqId` instead.
+ */
+#define SEQCMD_SETUP_UNQUEUE_SEQUENCE(setupSeqPlayerIndex)                                    \
+    Audio_QueueSeqCmd((SEQCMD_OP_SETUP_CMD << 28) | (SEQCMD_SUB_OP_SETUP_SEQ_UNQUEUE << 20) | \
+                      ((u8)(setupSeqPlayerIndex) << 24))
+
+/**
+ * Setup a request to restart and play an active sequence currently playing on a target seqPlayer
+ * once a setup seqPlayer is finished playing and disabled
+ *
+ * @param setupSeqPlayerIndex the index of the seqPlayer to wait for to be disabled
+ * @param targetSeqPlayerIndex the index of the seqPlayer to restart its active sequence
+ */
+#define SEQCMD_SETUP_RESTART_SEQUENCE(setupSeqPlayerIndex, targetSeqPlayerIndex)              \
+    Audio_QueueSeqCmd((SEQCMD_OP_SETUP_CMD << 28) | (SEQCMD_SUB_OP_SETUP_RESTART_SEQ << 20) | \
+                      ((u8)(setupSeqPlayerIndex) << 24) | ((u8)(targetSeqPlayerIndex) << 16))
+
+/**
+ * Setup a request to scale the tempo of a sequence by a multiplicative value on a target seqPlayer
+ * once a setup seqPlayer is finished playing and disabled
+ *
+ * @param setupSeqPlayerIndex the index of the seqPlayer to wait for to be disabled
+ * @param targetSeqPlayerIndex the index of the seqPlayer to modify
+ * @param duration duration to transition to the tempo
+ * @param tempoScale the scaling factor of the tempo, relative to 100
+ *
+ * @note a tempoScale of 200 will go double-time, 50 will go half-time.
+ * the absolute tempo is constrained to a maximum of 300
+ */
+#define SEQCMD_SETUP_SCALE_TEMPO(setupSeqPlayerIndex, targetSeqPlayerIndex, duration, tempoScale)                      \
+    Audio_QueueSeqCmd((SEQCMD_OP_SETUP_CMD << 28) | (SEQCMD_SUB_OP_SETUP_TEMPO_SCALE << 20) |                          \
+                      ((u8)(setupSeqPlayerIndex) << 24) | ((u8)(targetSeqPlayerIndex) << 16) | ((u8)(duration) << 8) | \
+                      (u8)(tempoScale))
+
+/**
+ * Setup a request to reset the tempo of a sequence to the original tempo on a target seqPlayer
+ * once a setup seqPlayer is finished playing and disabled
+ *
+ * @param setupSeqPlayerIndex the index of the seqPlayer to wait for to be disabled
+ * @param targetSeqPlayerIndex the index of the seqPlayer to modify
+ * @param duration duration to transition to the tempo
+ */
+#define SEQCMD_SETUP_RESET_TEMPO(setupSeqPlayerIndex, targetSeqPlayerIndex, duration)         \
+    Audio_QueueSeqCmd((SEQCMD_OP_SETUP_CMD << 28) | (SEQCMD_SUB_OP_SETUP_TEMPO_RESET << 20) | \
+                      ((u8)(setupSeqPlayerIndex) << 24) | ((u8)(targetSeqPlayerIndex) << 16) | (u8)(duration))
+
+/**
+ * Setup a request to play a sequence on a target seqPlayer once a setup seqPlayer is finished playing and disabled.
+ * This command is optionally paired with `SEQCMD_SETUP_SET_FADE_IN_TIMER` to set the fade in duration
+ *
+ * @param setupSeqPlayerIndex the index of the seqPlayer to wait for to be disabled
+ * @param targetSeqPlayerIndex the index of the seqPlayer to play the sequence
+ * @param seqId the id of the sequence to play, see `SeqId`
+ */
+#define SEQCMD_SETUP_PLAY_SEQUENCE(setupSeqPlayerIndex, targetSeqPlayerIndex, seqId)       \
+    Audio_QueueSeqCmd((SEQCMD_OP_SETUP_CMD << 28) | (SEQCMD_SUB_OP_SETUP_PLAY_SEQ << 20) | \
+                      ((u8)(setupSeqPlayerIndex) << 24) | ((u8)(targetSeqPlayerIndex) << 16) | (u16)(seqId))
+
+/**
+ * This command is an optional command before `SEQCMD_SETUP_PLAY_SEQUENCE` to set the fade in duration
+ * (see cmd above)
+ *
+ * @param targetSeqPlayerIndex the index of the seqPlayer to play the sequence
+ * @param fadeInDuration duration the sequence will fade in over
+ */
+#define SEQCMD_SETUP_SET_FADE_IN_TIMER(targetSeqPlayerIndex, fadeInDuration)                     \
+    Audio_QueueSeqCmd((SEQCMD_OP_SETUP_CMD << 28) | (SEQCMD_SUB_OP_SETUP_SET_FADE_TIMER << 20) | \
+                      ((u8)(targetSeqPlayerIndex) << 24) | ((u8)(fadeInDuration) << 8))
+
+/**
+ * Setup a request to restore a volume on target seqPlayer once a setup seqPlayer is finished playing and disabled.
+ * Specifically, it will only restore volume if the number of queued requests on the setup seqPlayer matches
+ * the number of sequences queued
+ *
+ * @param setupSeqPlayerIndex the index of the seqPlayer to wait for to be disabled
+ * @param targetSeqPlayerIndex the index of the seqPlayer to modify
+ * @param duration duration to transition to the volume
+ * @param numSeqRequests the number of sequence requests queued that must match the actual number of sequence requests
+ */
+#define SEQCMD_SETUP_RESTORE_SEQPLAYER_VOLUME_IF_QUEUED(setupSeqPlayerIndex, targetSeqPlayerIndex, duration,           \
+                                                        numSeqRequests)                                                \
+    Audio_QueueSeqCmd((SEQCMD_OP_SETUP_CMD << 28) | (SEQCMD_SUB_OP_SETUP_RESTORE_SEQPLAYER_VOLUME_IF_QUEUED << 20) |   \
+                      ((u8)(setupSeqPlayerIndex) << 24) | ((u8)(targetSeqPlayerIndex) << 16) | ((u8)(duration) << 8) | \
+                      (u8)(numSeqRequests))
+
+/**
+ * Setup a request to restore a volume on target seqPlayer once a setup seqPlayer is finished playing and disabled.
+ * Allows `scaleIndex` to be specified.
+ *
+ * @param setupSeqPlayerIndex the index of the seqPlayer to wait for to be disabled
+ * @param targetSeqPlayerIndex the index of the seqPlayer to modify
+ * @param scaleIndex the scale index of a seqPlayer
+ * @param duration duration to transition to the volume
+ */
+#define SEQCMD_SETUP_RESTORE_SEQPLAYER_VOLUME_WITH_SCALE_INDEX(setupSeqPlayerIndex, targetSeqPlayerIndex, scaleIndex, \
+                                                               duration)                                              \
+    Audio_QueueSeqCmd((SEQCMD_OP_SETUP_CMD << 28) |                                                                   \
+                      (SEQCMD_SUB_OP_SETUP_RESTORE_SEQPLAYER_VOLUME_WITH_SCALE_INDEX << 20) |                         \
+                      ((u8)(setupSeqPlayerIndex) << 24) | ((u8)(targetSeqPlayerIndex) << 16) |                        \
+                      ((u8)(scaleIndex) << 8) | (u8)(duration))
+
+/**
+ * Setup a request to disable (or reenable) specific channels on a target seqPlayer
+ * once a setup seqPlayer is finished playing and disabled.
+ *
+ * @param setupSeqPlayerIndex the index of the seqPlayer to wait for to be disabled
+ * @param targetSeqPlayerIndex the index of the seqPlayer to modify
+ * @param channelMask a 16 bit mask where each bit maps to a channel. Bitflag on to disable
+ */
+#define SEQCMD_SETUP_SET_CHANNEL_DISABLE_MASK(setupSeqPlayerIndex, targetSeqPlayerIndex, channelMask)      \
+    Audio_QueueSeqCmd((SEQCMD_OP_SETUP_CMD << 28) | (SEQCMD_SUB_OP_SETUP_SET_CHANNEL_DISABLE_MASK << 20) | \
+                      ((u8)(setupSeqPlayerIndex) << 24) | ((u8)(targetSeqPlayerIndex) << 16) | (u16)(channelMask))
+
+/**
+ * Queue a request to scale the frequency of an entire sequence on a target seqPlayer
+ * once a setup seqPlayer is finished playing and disabled.
+ *
+ * @param setupSeqPlayerIndex the index of the seqPlayer to wait for to be disabled
+ * @param targetSeqPlayerIndex the index of the seqPlayer to modify
+ * @param duration duration to transition to the frequency
+ * @param freqScale the scaling factor to shift the pitch. Ranged from 0-0xFF, with 100 mapping to 1.0f
+ *
+ * @note The base value for frequency, 100, is 10 times smaller than other frequency commands.
+ * 200 will double the frequency (raise an octave), 50 will halve the frequency (lower an octave).
+ */
+#define SEQCMD_SETUP_SET_SEQPLAYER_FREQ(setupSeqPlayerIndex, targetSeqPlayerIndex, duration, freqScale)                \
+    Audio_QueueSeqCmd((SEQCMD_OP_SETUP_CMD << 28) | (SEQCMD_SUB_OP_SETUP_SET_SEQPLAYER_FREQ << 20) |                   \
+                      ((u8)(setupSeqPlayerIndex) << 24) | ((u8)(targetSeqPlayerIndex) << 16) | ((u8)(duration) << 8) | \
+                      (u8)(freqScale))
+
+/**
+ * Queue a request to discard audio data by popping an entry from the persistent caches on the audio heap,
+ * once a setup seqPlayer is finished playing and disabled.
+ *
+ * @param setupSeqPlayerIndex the index of the seqPlayer to wait for to be disabled
+ * @param tableTypeFlag All tables with the flag `(tableTypeFlag & (1 << tableType))` will be discarded. Specifically:
+ *   `(tableTypeFlag & 1)` will discard the `SEQUENCE_TABLE`
+ *   `(tableTypeFlag & 2)` will discard the `FONT_TABLE`
+ *   `(tableTypeFlag & 4)` will discard the `SAMPLE_TABLE`
+ */
+#define SEQCMD_SETUP_POP_PERSISTENT_CACHE(setupSeqPlayerIndex, tableTypeFlag)                          \
+    Audio_QueueSeqCmd((SEQCMD_OP_SETUP_CMD << 28) | (SEQCMD_SUB_OP_SETUP_POP_PERSISTENT_CACHE << 20) | \
+                      ((u8)(setupSeqPlayerIndex) << 24) | ((u8)tableTypeFlag))
+
+/**
+ * Discard all setup command requests on a seqPlayerIndex by resetting the setup command queue
+ *
+ * @param setupSeqPlayerIndex the index of the seqPlayer to disable all setup commands
+ */
+#define SEQCMD_RESET_SETUP_CMDS(setupSeqPlayerIndex)                                               \
+    Audio_QueueSeqCmd((SEQCMD_OP_SETUP_CMD << 28) | (SEQCMD_SUB_OP_SETUP_RESET_SETUP_CMDS << 20) | \
+                      ((u8)(setupSeqPlayerIndex) << 24))
+
+/**
+ * ==== Audio Sequence Global Commands ====
+ *
+ * The global commands will apply to the entire audio system and all 4 sequence players
+ */
+
+/**
+ * Change the sound output mode
+ *
+ * @param soundOutputMode see the `SoundOutputMode` enum
+ */
+#define SEQCMD_SET_SOUND_OUTPUT_MODE(soundOutputMode) \
+    Audio_QueueSeqCmd((SEQCMD_OP_GLOBAL_CMD << 28) | (SEQCMD_SUB_OP_GLOBAL_SET_SOUND_OUTPUT_MODE << 8) | (u8)(soundOutputMode))
+
+/**
+ * Disable (or reenable) new sequences from starting
+ *
+ * @param isDisabled true to disable, false to enable
+ *
+ * @note this does not disable the sfx player
+ */
+#define SEQCMD_DISABLE_PLAY_SEQUENCES(isDisabled)                                                        \
+    Audio_QueueSeqCmd((SEQCMD_OP_GLOBAL_CMD << 28) | (SEQCMD_SUB_OP_GLOBAL_DISABLE_NEW_SEQUENCES << 8) | \
+                      (u16)(isDisabled))
+
+/**
+ * Restart the audio heap with the specified settings
+ *
+ * @param sfxChannelLayout index for different mappings between the 7 banks and the 16 channels
+ * @param specId index for the audio specifications to set high-level audio parameters
+ *
+ * @note: For sfxChannelLayout, There are 4 possible layouts indexed by 0-3.
+ * However, only index 0 is properly implemented. Other indices lead to bugs and softlocks.
+ */
+#define SEQCMD_RESET_AUDIO_HEAP(sfxChannelLayout, specId) \
+    Audio_QueueSeqCmd((SEQCMD_OP_RESET_AUDIO_HEAP << 28) | ((u8)(sfxChannelLayout) << 8) | (u8)(specId))
+
+#endif
diff --git a/soh/soh/Enhancements/TimeSavers/SkipCutscene/Story/Twinrova.cpp b/soh/soh/Enhancements/TimeSavers/SkipCutscene/Story/Twinrova.cpp
new file mode 100644
index 0000000000..3e800fb681
--- /dev/null
+++ b/soh/soh/Enhancements/TimeSavers/SkipCutscene/Story/Twinrova.cpp
@@ -0,0 +1,122 @@
+#include "soh/Enhancements/game-interactor/GameInteractor.h"
+#include "soh/Enhancements/game-interactor/GameInteractor_Hooks.h"
+#include "soh/ShipInit.hpp"
+
+extern "C" {
+#include "variables.h"
+#include "seqcmd.h"
+#include "src/overlays/actors/ovl_Boss_Tw/z_boss_tw.h"
+#include "assets/objects/object_tw/object_tw.h"
+extern BossTw* sTwinrovaPtr;
+extern void BossTw_SetupFlyTo(BossTw*, PlayState*);
+extern void BossTw_SetupWait(BossTw*, PlayState*);
+}
+
+typedef enum {
+    /* 0x00 */ TW_KOTAKE,
+    /* 0x01 */ TW_KOUME,
+} TwinrovaType;
+
+// Adjust alpha for spawning portals on the platforms
+extern "C" void BossTwShip_TwinrovaHandlePortal(BossTw* bossTw, PlayState* play) {
+    if (bossTw->timers[0]-- > 0) {
+        Math_StepToF(&bossTw->spawnPortalAlpha, 255.0f, 10.0f);
+    } else if (Math_StepToF(&bossTw->spawnPortalAlpha, 0.0f, 10.0f)) {
+        BossTw_SetupWait(bossTw, play);
+    }
+}
+
+extern "C" void BossTwShip_TwinrovaSetupHandlePortal(BossTw* bossTw, PlayState* play) {
+    bossTw->timers[0] = 80;
+    bossTw->spawnPortalAlpha = 1.0f;
+    bossTw->spawnPortalScale = 0.05f;
+    bossTw->actionFunc = BossTwShip_TwinrovaHandlePortal;
+}
+
+// Rise from below platform, then enter normal gameplay
+extern "C" void BossTwShip_Rise(BossTw* bossTw, PlayState* play) {
+    Player* player = GET_PLAYER(play);
+
+    Math_SmoothStepToF(&bossTw->actor.world.pos.y, 400.0f, 300.0f, 6.0f, 4.0f);
+    bossTw->actor.world.rot.y = bossTw->actor.shape.rot.y = Actor_WorldYawTowardActor(&bossTw->actor, &player->actor);
+    SkelAnime_Update(&bossTw->skelAnime);
+    Audio_PlayActorSound2(&bossTw->actor, NA_SE_EN_TWINROBA_FLY - SFX_FLAG);
+    Math_ApproachF(&bossTw->scepterAlpha, 0.0f, 1.0f, 10.0f);
+    if (bossTw->actor.world.pos.y >= 400.0f) {
+        BossTw_SetupFlyTo(bossTw, play);
+        if (bossTw->actor.params == TW_KOUME) {
+            Audio_PlayActorSound2(&bossTw->actor, NA_SE_EN_TWINROBA_LAUGH2);
+        }
+    }
+}
+
+extern "C" void BossTwShip_SetupRise(BossTw* bossTw, PlayState* play) {
+    Player* player = GET_PLAYER(play);
+
+    bossTw->actor.flags |= ACTOR_FLAG_ATTENTION_ENABLED;
+    bossTw->actionFunc = BossTwShip_Rise;
+    if (bossTw->actor.params == TW_KOTAKE) {
+        Audio_PlayActorSound2(&bossTw->actor, NA_SE_EN_TWINROBA_LAUGH);
+    }
+}
+
+// Wait for player to climb up to start fight
+extern "C" void BossTwShip_WaitHeight(BossTw* bossTw, PlayState* play) {
+    Player* player = GET_PLAYER(play);
+
+    if (player->actor.world.pos.y >= 150.0f) {
+        Flags_SetEventChkInf(EVENTCHKINF_BEGAN_TWINROVA_BATTLE);
+        SEQCMD_PLAY_SEQUENCE(SEQ_PLAYER_BGM_MAIN, 0, 0, NA_BGM_BOSS);
+        BossTwShip_SetupRise(bossTw, play);
+        // The spawn portal is drawn by the Twinrova type BossTw actor, not Kotake/Koume
+        BossTwShip_TwinrovaSetupHandlePortal(sTwinrovaPtr, play);
+    }
+}
+
+extern "C" void BossTwShip_SetupWaitHeight(BossTw* bossTw, PlayState* play) {
+    Player* player = GET_PLAYER(play);
+
+    // X and Z are swapped
+    bossTw->actor.world.pos.x = (bossTw->actor.params == TW_KOTAKE) ? -600.0f : 600.0f;
+    bossTw->actor.world.pos.y = 60.0f;
+    bossTw->actor.world.rot.y = bossTw->actor.shape.rot.y = Actor_WorldYawTowardActor(&bossTw->actor, &player->actor);
+    bossTw->unk_5F8 = true; // Hair activated
+    bossTw->actionFunc = BossTwShip_WaitHeight;
+}
+
+void RegisterTwinrovaSkipIntroCS() {
+    COND_VB_SHOULD(VB_PLAY_TWINROVA_INTRO_CS,
+                   (CVarGetInteger(CVAR_ENHANCEMENT("TimeSavers.SkipCutscene.BossIntro"), IS_RANDO)), {
+                       BossTw* bossTw = va_arg(args, BossTw*);
+                       PlayState* play = va_arg(args, PlayState*);
+
+                       if (bossTw->actor.params == TW_KOTAKE || bossTw->actor.params == TW_KOUME) {
+                           BossTwShip_SetupWaitHeight(bossTw, play);
+                       } else if (!Flags_GetClear(play, play->roomCtx.curRoom.num)) {
+                           // Twinrova
+                           SEQCMD_PLAY_SEQUENCE(SEQ_PLAYER_BGM_MAIN, 0, 0, NA_BGM_KOTAKE_KOUME);
+                           BossTw_SetupWait(bossTw, play);
+                           bossTw->visible = false;
+                           bossTw->actor.world.pos.y = -2000.0f;
+                           bossTw->actor.flags &= ~ACTOR_FLAG_ATTENTION_ENABLED;
+                       }
+
+                       *should = false;
+                   });
+
+    // Swap portal XZ to match new Kotake/Koume spawn position
+    COND_VB_SHOULD(VB_TWINROVA_SPAWN_PORTAL_TRANSLATION_KOTAKE,
+                   (CVarGetInteger(CVAR_ENHANCEMENT("TimeSavers.SkipCutscene.BossIntro"), IS_RANDO)), {
+                       Matrix_Translate(-600.0f, 232.0f, 0.0f, MTXMODE_NEW); // Ice/Kotake
+                       *should = false;
+                   });
+    COND_VB_SHOULD(VB_TWINROVA_SPAWN_PORTAL_TRANSLATION_KOUME,
+                   (CVarGetInteger(CVAR_ENHANCEMENT("TimeSavers.SkipCutscene.BossIntro"), IS_RANDO)), {
+                       Matrix_Translate(600.0f, 232.0f, 0.0f, MTXMODE_NEW); // Fire/Koume
+                       *should = false;
+                   });
+}
+
+static RegisterShipInitFunc initTwinrovaSkipIntroCS(RegisterTwinrovaSkipIntroCS,
+                                                    { CVAR_ENHANCEMENT("TimeSavers.SkipCutscene.BossIntro"),
+                                                      "IS_RANDO" });
diff --git a/soh/soh/Enhancements/TimeSavers/timesaver_hook_handlers.cpp b/soh/soh/Enhancements/TimeSavers/timesaver_hook_handlers.cpp
index f8e67442cd..23aba6f03e 100644
--- a/soh/soh/Enhancements/TimeSavers/timesaver_hook_handlers.cpp
+++ b/soh/soh/Enhancements/TimeSavers/timesaver_hook_handlers.cpp
@@ -1266,9 +1266,9 @@ void TimeSaverOnSceneInitHandler(int16_t sceneNum) {
             }
             break;
         case SCENE_SPIRIT_TEMPLE_BOSS:
+            // For Twinrova see Twinrova.cpp
             if (CVarGetInteger(CVAR_ENHANCEMENT("TimeSavers.SkipCutscene.BossIntro"), IS_RANDO)) {
-                if (!Flags_GetEventChkInf(EVENTCHKINF_BEGAN_TWINROVA_BATTLE)) {
-                    Flags_SetEventChkInf(EVENTCHKINF_BEGAN_TWINROVA_BATTLE);
+                if (!Flags_GetEventChkInf(EVENTCHKINF_BEGAN_NABOORU_BATTLE)) {
                     Flags_SetEventChkInf(EVENTCHKINF_BEGAN_NABOORU_BATTLE);
                     Flags_SetEventChkInf(EVENTCHKINF_NABOORU_ORDERED_TO_FIGHT_BY_TWINROVA);
                 }
diff --git a/soh/soh/Enhancements/game-interactor/vanilla-behavior/GIVanillaBehavior.h b/soh/soh/Enhancements/game-interactor/vanilla-behavior/GIVanillaBehavior.h
index 8689bc41a2..1831afe1e4 100644
--- a/soh/soh/Enhancements/game-interactor/vanilla-behavior/GIVanillaBehavior.h
+++ b/soh/soh/Enhancements/game-interactor/vanilla-behavior/GIVanillaBehavior.h
@@ -2005,6 +2005,31 @@ typedef enum {
     // - None
     VB_PLAY_NABOORU_CAPTURED_CS,
 
+    // #### `result`
+    // ```c
+    // true
+    // ```
+    // #### `args`
+    // - `*BossTw`
+    // - `*PlayState`
+    VB_PLAY_TWINROVA_INTRO_CS,
+
+    // #### `result`
+    // ```c
+    // true
+    // ```
+    // #### `args`
+    // - None
+    VB_TWINROVA_SPAWN_PORTAL_TRANSLATION_KOTAKE,
+
+    // #### `result`
+    // ```c
+    // true
+    // ```
+    // #### `args`
+    // - None
+    VB_TWINROVA_SPAWN_PORTAL_TRANSLATION_KOUME,
+
     // #### `result`
     // ```c
     // true
diff --git a/soh/src/overlays/actors/ovl_Boss_Tw/z_boss_tw.c b/soh/src/overlays/actors/ovl_Boss_Tw/z_boss_tw.c
index b0b79eaca9..b3adbd4e2d 100644
--- a/soh/src/overlays/actors/ovl_Boss_Tw/z_boss_tw.c
+++ b/soh/src/overlays/actors/ovl_Boss_Tw/z_boss_tw.c
@@ -178,7 +178,7 @@ static s8 sEnvType;
 static u8 sGroundBlastType;
 static BossTw* sKotakePtr;
 static BossTw* sKoumePtr;
-static BossTw* sTwinrovaPtr;
+BossTw* sTwinrovaPtr; // global for CS skip hook
 static u8 sShieldFireCharge;
 static u8 sShieldIceCharge;
 static f32 D_8094C854;
@@ -495,7 +495,7 @@ void BossTw_Init(Actor* thisx, PlayState* play2) {
             this->actor.world.pos.y = 400.0f;
             this->actor.world.pos.z = 0.0f;
             Audio_QueueSeqCmd(SEQ_PLAYER_BGM_MAIN << 24 | NA_BGM_BOSS);
-        } else {
+        } else if (GameInteractor_Should(VB_PLAY_TWINROVA_INTRO_CS, true, this, play)) {
             BossTw_SetupCSWait(this, play);
         }
 
@@ -512,7 +512,7 @@ void BossTw_Init(Actor* thisx, PlayState* play2) {
             this->actor.world.pos.x = 600.0f;
             this->actor.world.pos.y = 400.0f;
             this->actor.world.pos.z = 0.0f;
-        } else {
+        } else if (GameInteractor_Should(VB_PLAY_TWINROVA_INTRO_CS, true, this, play)) {
             BossTw_SetupCSWait(this, play);
         }
 
@@ -531,7 +531,7 @@ void BossTw_Init(Actor* thisx, PlayState* play2) {
         if (Flags_GetEventChkInf(EVENTCHKINF_BEGAN_TWINROVA_BATTLE)) {
             // began twinrova battle
             BossTw_SetupWait(this, play);
-        } else {
+        } else if (GameInteractor_Should(VB_PLAY_TWINROVA_INTRO_CS, true, this, play)) {
             BossTw_TwinrovaSetupIntroCS(this, play);
             this->actor.world.pos.x = 0.0f;
             this->actor.world.pos.y = 1000.0f;
@@ -3782,7 +3782,9 @@ void BossTw_SpawnPortalDraw(BossTw* this, PlayState* play) {
 
     Matrix_Push();
 
-    Matrix_Translate(0.0f, 232.0f, -600.0f, MTXMODE_NEW);
+    if (GameInteractor_Should(VB_TWINROVA_SPAWN_PORTAL_TRANSLATION_KOTAKE, true)) {
+        Matrix_Translate(0.0f, 232.0f, -600.0f, MTXMODE_NEW);
+    }
     Matrix_Scale(this->spawnPortalScale, this->spawnPortalScale, this->spawnPortalScale, MTXMODE_APPLY);
     gDPSetPrimColor(POLY_XLU_DISP++, 0, 0, 0, 0, 0, (s16)this->spawnPortalAlpha);
     gSPMatrix(POLY_XLU_DISP++, MATRIX_NEWMTX(play->state.gfxCtx), G_MTX_LOAD | G_MTX_MODELVIEW | G_MTX_NOPUSH);
@@ -3794,7 +3796,9 @@ void BossTw_SpawnPortalDraw(BossTw* this, PlayState* play) {
     gSPMatrix(POLY_XLU_DISP++, MATRIX_NEWMTX(play->state.gfxCtx), G_MTX_LOAD | G_MTX_MODELVIEW | G_MTX_NOPUSH);
     gSPDisplayList(POLY_XLU_DISP++, SEGMENTED_TO_VIRTUAL(gTwinrovaKotakeMagicSigilDL));
 
-    Matrix_Translate(0.0f, 232.0f, 600.0f, MTXMODE_NEW);
+    if (GameInteractor_Should(VB_TWINROVA_SPAWN_PORTAL_TRANSLATION_KOUME, true)) {
+        Matrix_Translate(0.0f, 232.0f, 600.0f, MTXMODE_NEW);
+    }
     Matrix_Scale(this->spawnPortalScale, this->spawnPortalScale, this->spawnPortalScale, MTXMODE_APPLY);
     gDPSetPrimColor(POLY_XLU_DISP++, 0, 0, 0, 0, 0, (s16)this->spawnPortalAlpha);
     gSPMatrix(POLY_XLU_DISP++, MATRIX_NEWMTX(play->state.gfxCtx), G_MTX_LOAD | G_MTX_MODELVIEW | G_MTX_NOPUSH);