This tsundere troupe has really gotten out of hand, it's ok to a certain extend and it might even make the story or character better if used correctly, but in this story it's absolute bullshit, if your friend has his life completely ruined and when you try to help him but he's too afraid to try...
so only like 10 people survived? if they killed each other, they should have gotten money which would let them survive unless there're weren't that much coins or most of them were taken by a small group of people basically monopolizing them by killing a lot of people, if that makes sense.
one problem that I have with this manga is that biologically some of the skills they use aren't possible no matter how hard you train, the human body has limits, you just can't go past it just from effort for example the double edge cut, you can't just swing once but cut twice normally and if...