This path would not be the one that he would choose, but it was the only viable option in front of him.
He would need to slaughter trillions of mortals and godly beings to gain the resources that he needed for his evolution, and he needed to be quick. His slaughter would have to take place in a portion of the universe that was heavily populated.
There was no consideration of whether he should risk himself and reveal his full might to the universe instead of killing so many mortals and immortals. In twenty or so years when the tainted blood of the universe reached the surface of reality, its vitality leeching properties would wipe out every life in the universe.
If their deaths could serve him now, it would be the best option for them. Rowan would keep their Soul Origin safe, freeing them from a destiny of endless reincarnation without choice.