Knight's & Magic

Knight's & Magic is a light novel by Hisago Amazake-no released in 2010 about a genius programmer and mecha otaku who dies after getting hit by a van while crossing the road and then reborn as an effeminate looking boy in a world where magic and his obsession, robots, exist for real. Learning that magic is a rather a lot like his previous's world's programming, he becomes a child prodigy with the goal of building his own Silhouette Knight (the term for robots in his new world).

In 2017 it was adapted into an anime