Gedomaru

She was a vicious demon who was caught and forced to work as Shikigami for Ketsuno clan. The only person she acknowledges and holds dear is Ketsuno Ana. When Gintoki Accepted job from Ketsuno Ana, she was assigned under his command.

SpoilerAt the end of Ketsuno Arc she tells Gintoki, that shen will never forget her second master

Seiyuu: Kawasumi Ayako

Wikipedia