Balder

Balder (or Baldr or Baldur) is the Norse god normally associated with beauty, light, and the sun. He is the son of Odin and Frigg. In the myths, Baldr is promised to be unharmed by literally everyone and thing in the world, except for one thing (normally identified as mistletoe), and is killed due to the machinations of Loki, thus kicking off the events of Ragnarok.

TMNT
At the end of the story Ragnarok, Balder appears suddenly to chastize the viking Ragnarok for his actions which were flooding the Earth. Balder froze Ragnarok in a block of ice, then healed Ruk the mutant walrus, leaving him as a mutant at his request. Balder's actions also restored the glaciers that Ragnarok was melting.

Powers and abilities

 * God physiology: It is unknown to what degree Balder's body was different from a human's, but it's likely he enjoyed the same perks as the actual Balder of Norse myth.
 * Cryokinesis: Balder instantly froze Ragnarok in a block of ice. It is also implied that he restored the glaciers this way.
 * Healing: Balder instantly healed Ruk's wounds.
 * Demutation (implied): Considering that Ruk asked to stay a mutant, he may have the ability to revert mutants to their original forms.