Fushichō Fukkatsu

Fushichō Fukkatsu (不死鳥復活, Phoenix Resurrection) is a Mangekyō Sharingan technique that has awakened in Kenshin Uchiha's eyes. This an ability that is unique to Kenshin which allows him to heal his own injuries. Though the exact workings of this technique are unknown, it is seen to be similar to how a phoenix rises from its ashes as while using this technique the aggrieved body part is enveloped in chakra infused light blue flames which pour chakra into his wounds to heal him. He needs large amounts of chakra to use this ability and though he can regrow body parts he cannot do so for his brain and vital organs.

Like all Mangekyō Sharingan users Kenshin also suffers from its drawbacks. Though using Fushichō Fukkatsu slowly reverts the blindness due to usage of Mangekyō techniques it does not stop it and extended usage of Mangekyō techniques leads to blindness for periods of time which vary depending on the amount of time for which Kenshin used the techniques. Also as the technique uses chakra to heal him, it can only be used when Kenshin has sufficient amount of chakra and though it heals him, neither does it take away fatigue nor does it replenish his chakra reserves.