|Romaji name||Tachibana Mutsuki|
|Cause of death||Crimson Sacrifice Ritual|
Itsuki Tachibana (twin brother)
Chitose Tachibana (younger sister)
|Appearances||Fatal Frame II: Crimson Butterfly|
Fatal Frame II: Crimson Butterfly Director's Cut
Fatal Frame II: Deep Crimson Butterfly (Wii Edition)
|Voice actor (Jp)||none|
|Voice actor (Eng)||none|
Mutsuki Tachibana was Itsuki's twin, and Chitose's older brother. Although Mutsuki was born first, the custom of Minakami Village declared him to be the younger twin. Both he and Itsuki agreed that the ritual was wrong and believed that there had to be another way to appease the Hellish Abyss. They considered running away to prevent participating, but according to Itsuki's diary, Mutsuki was too weak to attempt an escape when the time of their ritual drew near. They also realized that if they were to run away, their close friends Sae and Yae Kurosawa would be next in line to perform the ritual. The twins made a pact with each other that if their ritual were to fail, they would not to let Yae and Sae suffer the same fate they had.
The twins performed the Crimson Sacrifice Ritual, but Itsuki's love for Mutsuki was too strong. The ritual failed, and Mutsuki never became a Crimson Butterfly.
In the Promise Ending, the spirits of Mutsuki, Itsuki, and Chitose are reunited. The three stand together, looking up as the crimson butterflies leave the village.
- The name Mutsuki means "January" (睦月).
- Mutsuki's surname Tachibana means "standing" (立) (tachi) and "flower" (花) (hana/bana).
- While he is mentioned frequently, Mutsuki only appears on the ghost list and in the Promise Ending of Fatal Frame II.
- In Deep Crimson Butterfly, his vanishing ghost appears twice in the Tachibana House, and during the Crimson Butterfly Ending, a brief glimpse of Itsuki and Mutsuki's ritual can be seen.