Dracu-Riot!

Welcome to Aqua Eden — an artificial island off the coast of Japan where casinos and more are legal. On the very first day of his vacation, the protagonist witnesses a kidnapping and takes matters into his own hands, setting off a chain of events that turns him into a vampire. Now confined to Aqua Eden, our newly fanged hero finds himself embarking on an unforgettable new nightlife in a city where vampires wander moonlit streets. This is the story of a city with a utopian vision where humans and vampires are allowed to coexist.