Saisei

Saisei (再生) is the legendary kekkei genkai of the nearly extinct Soragokoro Clan that grants them the access of rapid cell regeneration ability. By constantly feeding their cells with chakra, they could regenerate any parts of the damaged body almost instantly. This ability was forgotten as the remained members of Soragokoro Clan are fewer than a single digit.

Abilities
The main and the most powerful ability of Saisei is to grant the cells a rapid regeneration. It is notable that normal human have the ability to regenerate some of their damaged body parts by complete or incomplete regeneration known as fibrosis. However, Saisei breaks the limit of normal healing method in a very huge margin. It grants faster regeneration that ranged from a couple of seconds instead of days and it can regenerate any part of the body and organs including heart and brain provided that they are not completely or badly damaged since both of them are the main operator of the mind. The most feared ability is it works even without the needs of consciousness from the user as long as there are sufficient chakra supply.

Although it may looks similar to immortality, it is totally wrong due to its various weaknesses that can be exploited. The cells of the user will consume more energy compares to normal humans and take a great chakra expenditure when they are actives. This always make them being located in a very disadvantage position while partaking in a long duration battle as their stamina and chakra decline faster than the others. Despite the body can regenerate anytime at a very quick speed, the pain will not be subsided. The user will still suffer from the affliction of their injured body like any other humans do.