Strange Creators of Outer World/Who's Who of Humans & Youkai in Gensokyo/Benben and Yatsuhashi Tsukumo

幻想郷人妖名鑑 九 (つ) 十 (く) 九 (も) 弁 (べん) 々 (べん) 九 (つ) 十 (く) 九 (も) 八 (やつ) 橋 (はし)	Who's Who of Humans & Youkai in Gensokyo Benben Tsukumo Yatsuhashi Tsukumo
楽器の付喪神✕２	Musical Instrument Tsukumogami (x2)
九十九姉妹は伝統楽器の付喪神だ。「輝針城」４面ボスとして初登場、その後エキストラの中ボスとしても登場した。	The Tsukumo sisters are tsukumogami born from traditional instruments. They first debuted as the stage 4 bosses of "Double Dealing Character" and also appeared as the EX stage midbosses.
彼女たちは針妙丸が使用した打ち出の小槌の魔力で妖怪として目覚めたばかりで、弁々は琵琶、八橋は琴の付喪神である。姉妹と言っても血縁関係にあるわけではなく、あくまでタイミングが同じだっただけだ。小槌の魔力で目覚めたという影響からか、素直に道具による下克上を夢見ていたようだ。なお「輝針城」の異変で針妙丸が退治されたあとも、打ち出の小槌の魔力が枯渇して単なる道具に戻らないように雷鼓から知識を得たらしい。	They woke up as youkai thanks to the magic power of the Miracle Mallet wielded by Shinmyoumaru, with Benben being the tsukumogami of a biwa and Yatsuhashi being the tsukumogami of a koto. The sisters aren't blood relatives, they were simply born at the same time. Perhaps because they had woken up due to the effects of the mallet's magical power, they appear to have been genuinely dreaming of overthrowing the strong by means of tools. Even after Shinmyoumaru was defeated at the end of the Double Dealing Character incident, it seems that they've gained knowledge from Raiko on how to retain the Miracle Mallet's magic power so that it wouldn't be exhausted and they wouldn't return to being mere instruments.

Comment from ZUN

Comment from ZUN

付喪神の原点「百鬼夜行絵巻」に登場する名前の無い妖怪をモチーフにしたくて、この二人になりました。「百鬼夜行絵巻」は見てて面白いですよね。横スクロールのゲームみたいな感じがすごくある。彼女らは生まれたての妖怪なので、どこで何をしていた、みたいな設定があまりないんです。ゲーム中だと、個人的には音符の弾よりも休符の弾のほうが避けづらい（笑）。

I wanted to go with the theme of nameless youkai from the Night Parade Picture Scroll, the origin of tsukumogami, and ended up with these two. Seeing the Night Parade Picture Scroll is pretty interesting, it really gives off the feeling of a side-scrolling game. They're both newly born youkai, so there isn't really much backstory to them, like what they were and what they were doing previously. Gameplay-wise, personally I think the rest note bullets are way tougher to dodge than the music note bullets (laugh).