Kisui Iyoku/Second Regeneration

Kisui Iyoku (きすいいよく) is a shinobi once hailing from Kumogakure before making Sunagakure his home after he was hunted down by the Land of Lightning. During his travels, he was brought to near death, which brought upon a sudden defense mechanism from his Celestial Being DNA. To prevent him from dying, his cells and DNA rewrote themselves, invoking a regeneration process that altered everything about him, save for his memory. In short, he's a new face, with the same name.

Background
Following his battle in the Land of Craters with Kosui Genmu, he was mortally wounded by Kokushi and brought outside of the Land of Craters. During this time, he bid farewell to the two spirits that once inhabited his body as they made their way to the Pure Realm. Afterwards, the regenerative energy enveloped his body and transformed him entirely. All of his abilities were gone except for the few he remembered from memory.