Kuchel Ackerman

Kuchel Ackerman is the unknown mother of Levi Ackerman, and sister to Kenny Ackerman.

History
Long after the persecution of the Ackerman clan, Kuchel took to working in a brothel in the Underground City. She ended up being impregnated by one of her clients.

Trivia

 * It's unknown who the client is, or whether he knows about Levi.