Tissue Regeneration

Description
Tissue Regeneration, or Healing Factor as it is sometimes referred, is the ability to restore damaged or lost tissue. Speed of regeneration is dependent on the individual, and generally increases in speed the more it is used.

Level 1
The user can restore all wounds within a matter of days, and is immune to minor illnesses.

Level 2
The user can restore all wounds within a number of hours, is immune to all illnesses, and doesn't age past their prime.

Level 3
The user can restore all wounds within a matter of minutes.

Level X
The user can restore all wounds within a matter of seconds.

Explanation
The user has a highly advanced stem cell that travels throughout their body and replicate itself into the needed materiel. These cells can replicate bone, nerves, muscle and even fully repair the spinal chord. These advanced stem cells are continually being produced, at level 2 and higher, even after an apparent "death".

Theories

 * Judging from the above explanation, you wouldn't need to eat or drink as these cells would morph into the appropriate substance. You would still get hungry get hungry and thirsty, but you wouldn't die because of lack of sustanence. You would also be weakened.
 * You wouldn't need to breathe oxygen to LIVE. You wouldn't die from lack of oxygen, but as there is still a deficiency and therefore the user would be unconscious.
 * Complete removal of the Stem Cell producing organ at the back of the head would essentially result in the death of you, as there would be a lack of stem cells to heal you.
 * If the Stem Cell producing organ at the back of the head is damaged, it can still produce stem cells for up to 3 days, even if the User is "dead". If the damage is repaired, the user can be revived.
 * The Stem Cell organ has its own supply of energy (like a spleen has extra blood). If the heart stops beating, the organ acts as a temporary heart, pumping the blood around the body for a short amount of time until the heart can be restarted or repaired.