Diabolik Lovers: Lunatic Parade

A famous demon collector from the Demon World has stolen Yui's heart and replaced it with a magic crystal—one that will gradually lose its power, threatening her life. The Sakamaki, Mukami, and Tsukinami vampire clans descend into the Demon World to retrieve what was taken, arriving in the middle of the grandest parade the Demon World offers. Recovering a human heart while navigating demonic politics is, predictably, more complicated than it sounds.