Hokuto Kuzuhara is a delinquent known throughout Sekai Private Academy. His way of life being so hated by his family that they give him an ultimatum—find a girlfriend within a year or move out. That said, though, months pass and he still has had no luck and it seems like he never will. It is then during this predicament that he is approached by the student council vice president with a plan that would both save him from moving out... as well as help her with her revenge.

Yuuki wakes up to find herself wearing a maid's uniform in a strange manor. After wandering into the dining room, she comes across five other girls, each in the exact same outfit. Soon, the girls learn that the manor is brimming with lethal weapons and an array of deadly traps…and that they can only escape by playing the most gruesome of games. As the terrifying truth sets in, each girl's face goes pale—except Yuuki's. Why? Because this isn't her first go-round. That's right—Yuuki is a professional death game player who lives off the prize money she collects from winning brutal killing competitions, and she's not about to let this chance pass her by. (Source: Yen Press)

[It’s a familiar dungeon.] Inside a medium-boss room of an RPG game that he played again and again until he can get there with his eyes closed, waiting for a hero, a demon who exists only to be defeated, got his former life memory revived. Knowing that, in his previous life, he was a nothing-special college student, he could not continue living as a to-be-defeated mid-boss. He was determined to defeat the boss and escape the dungeon. That which was obtained in the process was a doping item called “pearl piece” (JP: ”珠片”). He, the demon who was ordered by the goddess to collect the 15 pearl pieces that were scattered around the world, decided that while on this quest, he at least would enjoy travelling around his favourite RPG game world. His name would one day become the legend of the Demon God of Oeyama, and his tale the demon romance story.

A girl suddenly appeared in the living room of a young boy’s house. The girl was an elven girl that came from another world. That elven girl naturally had no place to go, so she ended freeloading at the boy’s house… An elven girl that became a freeloader, a very ordinary high school boy, and the boy’s childhood friends come together as the elven girl gradually gets used to another world. Centered around an elven girl that came from another world in an accident, a heart-warming everyday life story with an elf began.

Everything that happens in the world is settled through games.