Average high school student Mikagami​ Kouji is a hardcore gamer. One day he gets isekai'd and he only gets the skill "copy" which is apparently useless but we all know it's secretly OP or something. He's enslaved to be a gladiator by his summoner, the big booba, head priestess Zayd. He has to fight in the Colosseum and if he loses he gets raped.

Five days after the sudden appearance of zombies... The protagonist, Masaru, who is having it rough surviving at school, is splendidly saved from this predicament by high schoolers Sekigahara Miki and Nakiri Karin. Though Masaru is at first relieved, he ends up realizing their true intentions...!!

It was just a usual morning. Akira Shiroyanagi, a high schooler who loves games and Konpeito (Japanese sweets), has suddenly been dragged into a battlefield by a mysterious girl who calls herself Mion. The participants are told that they are "erased from the family register, involved in an experiment, and gained certain powers."
Akira is determined to win the game with his newfound powers and destroy the organization. Armed with a power no one expects and his "brain" skills, the new period of intelligence battle of begins!