Elf Tensei Kara no Cheat Kenkoku-ki - Chapter 19Book 1: -3: Battle

Summoned after an unfortunate accident in hopes they could protect the world from a coming threat, Ben and his classmates are gifted another chance at life. With fame and fortune promised to whoever is willing to fight for the sake of the world it doesn't seem like a bad deal, there's just one small problem. Ben wasn't blessed with any magic or combat skills, just crafting and enchanting. While the skills themselves aren't useless they also aren't seen as being necessary to the coming war. Now not needed and alone Ben tries to find a place in the world while meeting some of its colourful characters along the way.

Gu Nianzhi had no idea how to get the aloof and handsome Major General to fall in love with her.

His eyes were dark and serious. “…Seduce me. If you can do it, I’m yours.”

Gu Nianzhi: “!!!”

- Description from Novelupdates

16 years old-- most boys would be falling in love, as their hormones all rise to unprecedented levels. Most boys at Riley's age would have dreams; dreams that will slowly grow into passion. Riley, however, at age 16... killed the world's number 1 superhero.

A great demon king who came from another world to conquer Earth. To save the Earth, Li Luyou could only first take care of this great demon king… a little girl proclaiming herself Her Imperial Princess.

- Description from Novelupdates