Yosuga Mitsuzaki

Mitsuzaki Yosuga is a Deadman previously captured at Deadman Wonderland. After it fell, she joined Makina's expedition and return to DW to permanently destroy it and the Wretched Egg.

She tells that she's Sakigami Toto's big sister, and part of the reason she agrees to return to DW is to find out what happened to her brother. Later, a flashback shows that they aren't actual siblings. Yosuga is an orphan brought into DW by Tamaki, and Toto's family (including his older sister) had already died. It's implied that Toto claimed Yosuga as his older sister due to Yosuga's resemblance to her, although Yosuga is younger than Toto. As time went on, she started to think of Toto as her real brother.