Violent delinquent Oga encounters a baby one day, which crawls onto his back and immediately forms an attachment to him. Though he doesn't know it yet, this baby is named Kaiser de Emperana Beelzebub IV, or "Baby Beel" for short—the son of the Demon Lord!
The anime itself doesn't shine in any specific category, and probably some (few) parts/elements are "broken", but all in all it's warm/positive/funny. I didn't like much the first episodes but there weren't any hard reasons to stop watching it so I kept going => I didn't regret that decision - at around the first quarter I started liking it. The last episodes are, in my opinion, superfluous.