Hiii! Haha, well, maybe I can help 
I think this is redundant here. It tells me nothing about the story or the characters.
This is a good paragraph! I do have a few edits:
In his sleep, Shinichi was able to see the world's true form. Most importantly, he could level up people's abilities and eventually obtain those maxed-out abilities for himself! Thus, he began to collect as many powerful people as possible, so he could return to his former glory...
I like that we're upping the stakes here, the structure is a bit confusing though. How about...
An odd figure who may or may not be Shinichi's mother kept warning him of the dangers to come. "The world's devouring has begun," she cautioned, "and it won't stop until everything's consumed." Or something.
And here I think restructuring could help it flow better:
Well...who cares about the end of the world, anyway? He has other things to do. Best to ignore these ominous warnings that aren't going to help his current situation.
Well, those would be my suggestions! Hope they helped but feel free to ignore them if they didn't!