Nine Hells Regeneration

The Nine Hells Regeneration is a special [---] of members of the Fukkatsu Clan. It grants them a heightened healing factor while allowing them to adapt at will to techniques that damage them while granting them access to the offending technique.

Drawbacks
While the user can become immune to techniques and their damage, after adapting a ninth technique, adapting any further will overwrite the first adaptation. This can be taken advantage of by opponents with a wide variety of techniques. Another disadvantage their ability holds is that if the user is affected by a technique capable of killing them instantly, such as soul removal or atomic obliteration, their body won't adapt to it.