->''"[[UnreliableNarrator Long long ago, in a certain place,]] [[BlatantLies there was a very handsome, cool, well-respected, entirely angelic young man...]]"''
This is the story of up-and-coming [[JapaneseDelinquents delinquent]] Tatsumi Oga, a first year at the infamous Ishiyama High, who one day suddenly finds himself [[ActionHeroBabysitter unintentional foster parent]] of the Demon King's son, Kaiser de Emperana Beelzebub IV (Baby Beel for short), an [[KillerRabbit adorable baby boy]] who is destined to [[EndOfTheWorldAsWeKnowIt destroy the world]]. Initially [[RefusalOfTheCall reluctant]] to carry out his fatherly duties, Oga changes his mind when Baby Beel's [[NinjaMaid wetnurse]] and "mother" Hildegarde shows up, with the news that Oga [[JoinOrDie will be killed]] if the contract is broken, and he must face his responsibilities. That is, unless he can find [[AsskickingEqualsAuthority someone even stronger]] to take over from him...
A [[CrazyAwesome delightfully absurd]] gag manga with liberal doses of action by Ryuhei Tamura, ''Beelzebub'' started out as a one-shot before being serialized in ''Magazine/ShonenJump''. The plot consists mainly of [[IdiotHero Oga]] dealing with the problems of raising Baby Beel, while fighting his way through the ranks of demons and troublemakers he encounters, often to [[HilarityEnsues hilarious results]].
An OVA was shown at the 2010 Jump Super Anime Tour. The anime adaptation began airing January 2011, ending in March 2012.
The manga ended in 2014 after 240 chapters, with a spin-off that started May 2014 known as ''Beelzebub Side Story''.