You've fallen into the Underworld. Fret not, you're not alone...but these people are...?

A self-produced four-person unit led by the prodigial son of a talent agency's CEO. Each member is assigned a mythical creature or concept who resides in the Underworld. They have a rather dark theme and are known for their mature image, as well as their fanservice. Their discography tends to vary a lot, and each of their music videos have certain lore to them.