問題不良少年研究所 R.esearch I.nstitute of P.roblematic D.elinquent B.oys officially titled the PROBLEMATIC DELINQUENT JUVENILE BOYS RESEARCH INSTITUTE is an underground organization within 学園都市 Academy City’s dark side, directly under the control of the city’s upper management. All of its members are adolescent boys and young men.

On the surface, it presents itself as a juvenile research institution. In reality, however, it is a covert assassination unit kept and directed by a certain high-ranking member of the 統括理事会 Board of Directors, functioning with the nature of mercenaries. Its primary mission is to carry out eliminations where the targets must “completely vanish from the world, leaving no trace of their remains.”

Every boy capable of joining RIPDB possesses some sorts of unique abilities. Specifically, RIPDBoys all have powers that allow them to devour and digest their targets, thereby ensuring that no trace or evidence is ever left behind.