Regeneration

Regeneration is the ability to regrow certain body parts or cells that have been dismembered or destroyed and replace them with brand new cells, or simply regrouping all of their separated parts back together.

Overview
There have been several beings capable of this, although each mysterious being has had different types of regeneration and different ways they have regenerated, and differed in how much time it takes to regenerate their bodies and whether they recreate cells in their body or regroup cells back together.

Some humans and mysterious beings have a weaker version of this ability, and are able to regenerate fractured bones or mutilated body parts.