Where to start . . . i guess I'll start at the finale, in the last 15 or so chapters things went crazy, I've heard of religious symbolism, but this is basically a religious deepthroat. The main character is a guy named riki who goes to jail (that's the worst arc btw) and just decimates prison bullies, most of the time big bads have an out of nowhere redemption and then double cross him like "oh wow villain number 400 stabbed riki in the back, what a twist, I'm so incredibly shook" and i think the author has a fetish for swords, one arc the big bad had a meteor sword and shortly after breaking it he goes on a rant and then gets like 3 more swords. There was a gay character, and it felt really really wrong, the author made the gay character into a crazy guy who's obsessed with his dead sister. The beginning arc was incredibly bland, the finale two arcs ended up going at 100 miles an hour and the BBEGs reason for his evilness felt like a huge asspull, did the author think to himself "how can we make the genocidal rapist into a semi redeemable character" and then went and saw starwars and somehow the editors didn't call him out on his B.S.
Tl;Dr read FOTNS instead if you want a manga about manly men punching other manly mens heads off.