Kreus

Raki raki no mi

It would be nice if the protagonist or the system merges the Kryptonian + Sunshine type bloodlines. Kryptonian physique would nullify Sunshine's weaknesses and allow to use The one freely and Sunshine could be used to control the sun's energy for more variety of uses (cruel sun) of course all this with much more power. Different fusions could also be done eg Gilgamesh + Haki.

instead of the God of Haki it would be better if it is called the God of Will