Warning: This song contains questionable lyrics and themes (Violence, suicide); it may be inappropriate for younger audiences.
The Vocaloid Wiki does not have a policy on lyrical content or theme; however, it attempts to follow the Wikia TOU.
For further discussion see this discussion post. Questionable songs are automatically sorted into this category.
Romaji: Watashi no Nanatsu no Oiwai ni
English: On My Seventh Birthday
Uploaded May 21, 2013, with 81,000+ Niconico views, 680,000+ YouTube views, and 21,000+ SoundCloud views
The song introduces the two main characters of the series, the slightly-older Tsukuyomi and the slightly-younger Amaterasu during their shared seventh birthday, establishing their familial bond of being fraternal twins. While the two are very close, a petty dispute and accumulated hatred causes Amaterasu to kill Tsukuyomi by a blow through the abdomen with a staff.
While the illustration of the two sisters being impaled on the same staff may be misleading it can be inferred that it serves as metaphor for the consistent theme of the two "being one" as well as their eventual shared pain and confusion.
Part of masa's album ADULT, this version of Watashi no Nanatsu no Oiwai ni is a remake of the original song featuring much of the previous arrangement as well as new instrumental arrangements and lyrics.