Kugane Maruyama originally posted Overlord under the handle Muchimuchi Puririn, but switched to his current pseudonym once the series got picked up for publication. He figured readers would raise an eyebrow buying a book by someone whose username basically translates to "blubbery fatty."
His short story "Dawn" was adapted into Kagetsu Tohya, Type-Moon's sequel to the doujin visual novel Tsukihime, which came out in August 2001. Even Nasu Kinoko, the writer behind Fate/stay night, gave his work genuine praise—but Maruyama admitted he stepped back from pursuing writing seriously after realizing the talent gap between himself and Nasu was just too wide.
A longtime Dungeons & Dragons enthusiast, Maruyama actually got back into writing partly because his gaming group kept getting too busy to meet up. With nobody around to play with, he needed something to do.
Content compiled by AnimeList.moe from publicly available sources.