The "White Wolf Tengu". Stage 4 midboss of Touhou's Mountain of Faith.
A wolf tengu with the ability to see great distances who patrols Youkai Mountain. For lack of official art, she is commonly depicted with wolf ears and tail, even if inconsistently shown in official side manga. She is known for her cooperative and dutiful personality, so early fanworks often portrayed her as loyal and puppy-like to Shameimaru Aya, but it was later revealed that she dislikes Aya and will not take orders from her since they belong to different chains of command.
Genderswapped/trap (otoko no ko) Momiji is very popular, and is tagged as ショタ椛 on Pixiv.
She has short white or grey hair with medium-length bangs and usually has fluff in her ears and red or brown eyes. She wears a small red tokin hat with dangling pom poms, a sleeveless white shirt with a turtleneck, ribbon-trimmed detached white sleeves, a two-tone black and red skirt with a maple leaf print, and tengu-geta. She usually carries a sword and a shield.