This is a non-starter for the 1st 20 or so chapters. Too much drama and not enough working on the various mysteries that were set up.
Also, the pointless fighting between MC and his sister is so forced. I don't blame the sister for "being annoying" as so many have commented on various websites.
Literally NO ONE tells her what's going on. She doesn't understand what her brother has gone through because the asshole never tells her anything. She doesn't understand that he really is all powerful... even if she's already seen him go nuts on a bunch of monsters.
Honestly, she's still that lost, scared, orphaned girl after her brother disappeared. No one is reassuring her of anything. Now the pink haired chick seems to have an even closer relationship with her brother than she does. They share secret knowledge. They share experiences. They went through something in a place that she'll never know or ever get to go too. (Currently.) So, she's feeling even more isolated and pushed out, uncared for.
But none of that is made compelling enough for me to care about. This is boring.
EDIT: Tried again and it's still excruciatingly painful. I can't stand sports/tournament arcs when it's so fucking obvious it's not going to be all that important in the grand scheme of the story. Why introduce it at all?
And why do it at the very beginning when MC just got back to earth? It's mind-numbingly boring.