[[Doujinshi]] circle. Crimson is also the name of the main artist herself. The illustrator of [[Aoi Sekai no Chuushin de]].

Her works are well-known for distinctive meme-ish phrases.
For example: "くやしい...! でも...感じちゃう...!" or "ピクンピクン".

Pen-name: クリムゾン (Crimson)
Circle name: クリムゾン (Crimson) or クリムゾンコミックス (Crimson Comics)
Old circle partner: カーマイン (Carmine)
crimson comics