A serial killer with 200 IQ get sentenced to the gallow then isekai'd in parallel world hoping to find his dead kanojo that's been graped and murdered in previous world. First, what a shameful display, MC boasting about how people are jealous of him because he's a genius but failed to get higher score than Ted Bundy (136 IQ). Granted he's probably not a psychopath, but his motives are enough to murder 15 people only to fail, skill issue tbh. I don't know much about science but in this manga apparently a solar flare strikes the earth and wiping all the Y chromosomes from all Mensturning them into a state of psychosis becoming deranged and in a constant hunt for Y chromosomes, fulfilling the Feminist's ideal apocalypse world fantasy by raping killing and cannibalizing womens, instead of slowly dying of Alzheimer or any other disease. Yeah.

Even in the harsh world settings MC swore voluntary celibacy because of the trauma of his dead kanojo thus denying the mankind survival by refusing to become a sperm donor for his hot Sensei, while broken down crying "I Hate Mens". Very emotional 200 IQ guy, Maybe Author wanted to pander to certain demographics so they can self insert into mindlessly killing mens with no remorse as greenlighted by the plot, but that doesn't seem to work now does it lmao.

TLDR: this is just a twist of World's End Harem but with senseless killing while keeping the same soyboy MC. Art is ok, horrible writing, ineffective shock value, no impact gore and most importantly i can't self insert as a gay MC like this.