Tsukumogami of an Aging Biwa.

"All the other tools like me have gained power. We've behaved ourselves so far, but it'll be our era from now on."

Benben Tsukumo (九十九 弁々 Tsukumo Benben) is a tsukumogami, transformed from a biwa. She is the older sister of Yatsuhashi Tsukumo, though they are technically not blood related, and just became sentient at the same time.

She made her debut in Touhou 14: Double Dealing Character, either as the midboss or main boss.