Kasugai Crows

Kasugai Crows (鎹鴉 Kasugaigarasu) are crows that are used by the Demon Killing Corps, primarily for communication. Each of them is assigned to a Demon Slayer Corps member. They deliver missions to their designated members.

Description
These crows are special in that they can speak in full sentences, though their speech is very loud and limited. Most generally look and speak similarly, exceptions being Muichiro's crow, who has feminine eyelashes and can speak normally most of the time, and Zenitsu's Kasugai Crow, Ukogi, who is actually a sparrow instead of a crow and can’t actually talk.