Demon Lord 2099, Vol. 3 (light novel)

Demon Lord Veltol’s search for his missing retainers brings him to Yokohama, a metropolis that broke away from the continent and is now a solitary island in the middle of the ocean. This so-called “Meta-Utopia” is full of mystery and intrigue…and it’s home to a massive prison ruled by an entity who has some nefarious schemes.
Veltol, meanwhile, has a plan of his own: He’s breaking into jail!