I remember reading a novel years ago. It was about a guy who became a planet. He started off as a small planet and crashed into other planets to get bigger. Then he started to make creatures. He made humans, dragons and Godzillas. His planet got attacked by Aliens/Xenomorphs. He gave humans the ability of regeneration. Then he has the Godzillas kill all the Aliens. He can become an avatar of any species from his planet. His battle form is the strongest Godzilla. I can’t recall if it was a Chinese or English novel. It may have been untranslated.