The "Wicked Hermit Who Passes Through Walls", also nicknamed Seiga Nyan Nyan (青娥 娘々 [せいが にゃんにゃん]), lit. Lady Seiga. Stage 4 boss of Touhou's Ten Desires and owner of Miyako Yoshika respectively. Often also seen with Ibaraki Kasen as a fellow hermit.
Her name came from the title and name of the heroine of 青娥, an episode from Strange Tales from a Chinese Studio Volume 7.
She has blue eyes and short blue hair with drill sidelocks and her hair stick through her hair rings. Her outfit is a blue dress with puffy short sleeves, a collared open white vest, a blue belt with a white flower, white socks, and black shoes. She is often holding her ofuda or her hagoromo.
Seiga's hair stick is actually a "Wall-Removing Chisel" that lets her pass through walls. It is likely based on a chisel-shaped magical digging tool that appeared in Strange Tales from a Chinese Studio.