Machiya seriously needs to buy a fking gun and body armor already. He's got a ton of money, and clearly Mashiro can get them since she already acquired one for the teacher. Also, he should have collected the guns from the gun girl in the school. But I guess author-baka decided that he has to hold the idiot ball the entire series. Let's see who dies next that he could've saved via a gun, first one was his sister.
Also, how is mc and fmc not shacking up already? Is he a eunuch? Has she stopped trying to seduce him? I think the author is holding the True idiot ball.
Also a katana can't clean cut through bone, Japanese metal js shit thats why it needs to be folded so many times. Maybe a claymore would stand up to all that abuse from peoples bones but again manga logic means katana are the best swords evarrrrrr.