Kuchel Ackerman

Kuchel Ackerman ( クシェル・アッカーマン Kusheru Akkāman ) was the 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. Kenny Ackerman eventually finds her and tries to convince her not to keep the child; to which she refused and decides to raise the child.

At some point, several years after Levi is born, she gets sick and dies. Kenny comes to visit her not long after her death. He is surprised by how much weight she has lost. Then he is notified by a young Levi that she's already dead. Seeing Levi near death, and not being as heartless as he thought he was, he takes Levi to raise him as his own.

However Kenny abandoned him after some time. Many years later, he told Levi that he is his uncle. When asked why he abandoned him, Kenny said he wasn't fit to be a parent.

Trivia

 * It's unknown who the client is, or whether he knows about Levi.
 * It's unknown what caused Kuchel's death.
 * In the Underground City, she goes by the name Olympia. This is likely the name she uses when working, as her employer seemed aware of her first name.