The translation is strangely way off. For the last page , The white bubble are the girl text and should translate as"nononono", "Iamsorry, iamsorry, release me, help " and the black bubble should say " whywhywhy" "even though I waited and went as far as becoming like that." The god had crack and black spot meaning that he was transforming into something like a fallen/evil entity. He chose to survive and transform to keep their promise. Clearly the girl grew up and just forgot about it.