シスターシスター (Sister Sister) is an original maimai song by the circle せきこみごはん (Sekikomi gohan), featuring Hatsune Miku on vocals. Released for maimai DX PRiSM on December 20, 2024, it arrived as part of BLACK ROSE chapter 10, continuing the verse-driven narrative tradition that maimai original songs have cultivated over multiple editions. The track runs at a steady 150 BPM and clocks in at 2 minutes and 33 seconds. The song belongs to the Kotonoha Project (言ノ葉Project) 2nd Season as Side Story Essence 10, a story-focused Vocaloid music series that weaves lyrical narratives across multiple songs and artists. Its flavor text, a short prose passage displayed in-game, introduces Eleanor (エレノラ), a young woman reflecting on her past and the arrival of a beautiful young man who upended her quiet village life. The text hints at unavoidable tragedy, a sister relationship strained by mutual fear of understanding, and Eleanor's introspection as she gazes at her own mirror image now the same age as her sibling. Musically, the track pairs a driving pop-rock arrangement with Hatsune Miku's signature vocal synthesis, while the lyrics explore themes of love, faith, imprisonment, and redemption, "赤い血よ 咲き鎮め / もう天(あなた)の祝福は要らない" (Red blossom, settle down / I no longer need your blessing). The song's movie/illustration was handled by kotose and しきみ, giving the narrative a visual identity that complements the in-game jacket artwork. On the charting side, the Expert difficulty was designed by 鳩ホルダー (Hato holder) and the Master difficulty (level 13, constant 13.2) by Luxizhel, each bringing their own approach to the note placement across a 746-note Master chart that mixes standard Tap/Hold patterns with Slide, Touch, and Break elements.