The "White Wolf Tengu". Stage 4 midboss of Touhou's Mountain of Faith.
A wolf tengu with the ability to see great distances. For lack of official art, she is commonly depicted with wolf ears and tail, even though she lacks at least the former in her in-game sprite and official source cameos (barring Oriental Sacred Place, which is either the artist's creative input or him being uninformed), as well as the only character besides Hakurei Reimu and Kochiya Sanae to wear long, detached sleeves. Momiji patrols and guards Youkai Mountain. 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.
Person: wolf ears, wolf tail, short hair, white hair, grey hair, red eyes
Outfit: white shirt, sleeveless shirt, turtleneck, detached sleeves, ribbon-trimmed sleeves, bare shoulders, black skirt, red skirt, multicolored skirt, medium skirt, tengu-geta
Accessories: tokin hat, pom pom (clothes), sword, shield, maple leaf