Alien Nephalem physiology
Backstory: Helos was once a Deva (No, not the Overwatch character) a spirit in charge of looking after every natural force to exist until he grew tired of the little but constant threats and then decided to find out about his heritage. he learned that he was the offspring of an Angelic-alien mother and a Demonic-Alien father. He also learned of his ability to become a powerful singular being. So he traveled the omniverse to find his alternate selves so he can absorb them and become powerful to protect any universe from threats.
Custom power explanation:
Alien Nephalem physiology: since Helos was born from two alien parents from heaven and hell he possesses the abilites of a nephalem as well as general alien abilites.