Welcome to the world where assholes are everywhere. Where OP sages control everything and people are summoned from other worlds(or rather, seemingly only japan because it makes TOTAL sense that mass summoning again and again and again would only be from one tiny country in this world, would probably kill them to have someone from another country... Get this, they're not even called "otherworlders" or something, they're just called "japanese", pfft).
Upon arrival, all of them(except for the mc and another girl and two more who promptly died to dragon dck, no I'm not exaggerating here, they literally died from being penetrated by the very first monster that appeared) gain some kind of "gift" powers from the sage leader(probably?) which is kind of a system with powers, levels and shit. This system also conveniently removes their adversity to manslaughter, they essentially all become major asholes.
We're then introduced to a world full of shtheads who kills other people for whatever minor thing they can imagine. They'll kill when people look at them, they'll kill when people talk to them, they'll kill when people don't laugh at their jokes. They'll probably also kill you if you don't take a piss with the toilet seat up or if you fart in their near vicinity. I can imagine how they'd annihilate an entire city if it blocked their way, because walking around it is for losers. We're talking about power tripping morons with godlike powers granted to them all of a sudden while also removing their moral limiters. It's pretty much a twisted world with people from places here and there(not only japan or this world) and stuck-up btches everywhere. It's rarer to find someone who doesn't deserve to die than someone who does.
So, of course this would be a horrible world for the mc to be in, right? I mean, sht, this place is more filled up with crazy people than the madhouse. BUT! Here comes the twist, or rather the title reason, the mc is weak physically but also probably the scariest person in that entire world, to the point that no one would want someone like him in their world. I don't know if he's a supreme death god incarnate or something but he's got this weird power(which he had even on earth) that makes him able to kill EVERYONE. I mean fcking everyone. He just need to think about it when he sees them. But, of course that wasn't sick enough, so he can also trace malice/killing intent. This means that he can easily, despite his weak physique, kill anyone intending on killing him and evade attacks and sh*t like that. Oh, did I mention how he can sense malice through objects or creatures? So he can kill the origin of it all as long as they display killing intent. Doesn't matter where they are, if they can reach you, you can reach them.
"But, Seregosa, surely that would be the end of it, right? I mean, that's just too OP already..." you say? Yeah, one would think that. However, this motherfcker is intent on making sure that people and things shouldn't be able to stop him. So, he can kill individual body parts if he wants to. If he kills your vision, your hearing, your nose or whatever, it will disappear and forever at that no matter what you do. Well, that's essentially the same as killing them, so it's not a big deal, but imagine if he used that on someones dck? Now that's scary. Well, jokes aside, this power is trying to aim for the top spot of scary powers, so it's actually not limited to biological objects. You see, not only animate things, it can also kill inanimate ones. It doesn't matter if you're a robot, magic/spell, clothes, magic wands, a spirit, wall or any other object, this guy can kill ALL OF IT and by that I mean ALL OF IT. ANYTHING he wants to kill will break into pieces/cease to function, so don't mention your emotions to him because he might decide to try and succeed with killing someone's emotions. Wouldn't surprise me if he could kill someone's love, pride, hate, happiness or anything else like that. Sure, it hasn't been stated yet and it sure as hell sounds a bit too ridiculous even for this power, but I wouldn't be surprised if it happened.
So, let's go on a journey with this protagonist and a wacky girl. The mc seems to be on horse tranquilizers 24/7 becuase he just doesn't give a fck about anything or anyone as he just goes with the flow and doesn't even seem to care about his own situation or the journey(I mean, this is the guy who just kinda wondered what his spasming dragon-pens penetrated classmate was penetrated by and was busy finding that out rather than actually care about that classmate or him dying right by his side and he just picked up his game to play monster hunter after finding it out and killing the dragon instantly). He just kills people who he feels he should kill, which is most people. The girl is somehow almost instantly immune to the fact that people are dying, seems it has to do with her heritage.
Seriously, this mc doesn't give a single fck about ANYONE or anything. Which is pretty much a plus if you're tired of the standard japanese mcs that never kills anything humanoid. This guy not only kills everyone that threatens him, he makes it a habit to kill plenty of women as well because he doesn't give a single flying fck about gender. He even killed a wolf/cat-eared sexy girl very close to the start after she told a fake sob story. He also doesn't always even check who directs killing intent at him and kills them before even seeing them if they're a threat. A fun guy.
I truly recommend this manga(and the novel, though the translation for v2 and v3 is utter garbage which even ruins the novel and I hope someone retranslates it), but for you to like it, you need to feel like the stuff I've mentioned is acceptable or even fun/interesting. A mc that doesn't give a single fck and kills plenty of people in a world full of dcks.