rei (cookie)
Voice of Kirisame Marisa in Cookie☆☆ S3 and Onozuka Komachi in Halloween☆. Typically portrayed in her kaoru式 MMD model which is based on Forbidden Scrollery's Marisa, wearing a black coat with buttons, black gloves, a petticoat, and a purple hair bow. Extremely commonly depicted as a male crossdressing otoko no ko due to her husky voice.
Despite having a similar voice to Azusa and Mars, she is far worse at singing which became popular in its own way.
Because of how often Rei is depicted as male, identifying their gender solely based on the image can be difficult or impossible. If the artist has tagged the image or written commentary with RIくん or RI君, then they are a male. Other hints can be: Sananana creeping on them, the artist drawing Rei as male in previous images, or the comments on the image. If there is absolutely no indication of Rei being male, then tag them as female.