Board Thread:Wiki Discussions and Support/@comment-25442883-20150106172019/@comment-26112212-20150109150611

There are many things that are unclear and this one is no different. I'll just simply answer.

Regeneration Ability is just an ability unlike normal cells, Hashirama's cells heal  the wounds faster, It's ninjutsu but not a technique, it has chakra presumably Hashirama's chakra and it doesn't require any hand seals. It grants this healing power to any user who possesses Hashirama's cells, Madara regenerated half of his body in mere moments when he became Ten-Tails Jinchuriki. It's strange that we didn't get to see any of the healing ability from Hashirama. I guess he has more healing power than X-men wolverines; I didn't see a scratch on him.

Ten-Tail was hard to control after some of it's transformation stages, Obito had one Rinnegan so Madara advised him to use Hashirama's cells to control the Ten-Tails transformation. It has some stabilising effects. Danzo also used this for using multiple Sharingan.

It all started after the battle between Madara and Hashirama, Madara applied Hashirama's flesh bitten by him onto his wound, several years later he acquired Rinnegan, because he was Reincarnation Indra and Hashirama was Asuras'. Hashirama's cells were cultivated by Madara in statue, and afterwards they were used for creating White Zetsu Army. Only some people have wood release after experimentation on Hashirama's cells. I think Kurama's and healing abilities of everyone are from Sage, so his descendant's having those is a natural thing. Senju clan and their cousin Uzumaki clan descended from Asura Ootsutsuki so they have more life force and healing abilities.