In short the story is about a 25 year old gets transmigrated to a world with monster, killing whom grants you skills. Has a big sister who needs him in his team so he has to become stronger fast which seems to be the short term Boss fight. The story isn’t all vanilla, Some dark sides of human character is already shown. Overall with a humorous MC and nice side characters the book looks great.Details:World background: Earth has opened portals to various planes which are filled with monsters. Humanity evolved by killing this monsters and taking their skills.Mc: The trucksan was on holiday so the transmigration Of MC was done by slapkun. Mc is a 25 year old in a 15 year old’s body. He is quite likeable. Isn’t a psychopath, So killing monsters did affect him at the start. So far he is quite calm about things, and uses his brain. Though because he is new to the world most of his training path is decided by his sister.Cheat: At the starting base his powers are both good and bad for him, He only has 9 skill slots while even the most average people have 15-17 slots. But the cheat allows him to save 2 skills in 1 slot and they are able to be upgraded. But his body is too weak so his cultivation speed is very slow compared to how much his upgraded skills cost. Side characters: Currently the two most focused side characters are MC’s sister her best friend Both of whom are strong high schoolers. Their relationship is quite smooth for now. The Mc also got to know some schoolmates not sure if they will continue to be there in the story. So far it looks like if the Author introduces a named character he doesn’t just let them go after a chapter, But keeps using them so its not a waste to remember their names.