You can catch the first episode and the rest of the series on several major streaming platforms: Offers the full series for subscribers.

The story centers on Tatsumi Oga, a ruthless first-year student at Ishiyama High, a school notorious for its juvenile delinquents. The pilot effectively subverts standard hero tropes; instead of a protagonist seeking justice, Oga is a "juvenile delinquent in training" whose life changes when he discovers a giant man floating down a river. The man splits open to reveal a green-haired baby—the future Demon King—who immediately takes a liking to Oga’s violent nature. This premise instantly creates a "fish out of water" dynamic (or rather, a "demon in a high school") that fuels the episode's humor and action. Characterization and Voice Performance

What Happens in Beelzebub Episode 1: "I Picked Up the Demon Lord"

Oga’s strategic and easily panicked best friend serves as the vital "straight man" to Oga’s absurdity. The dub voice actor nails the comedic timing, delivering frantic reactions to the supernatural madness unfolding around him.

The Ultimate Guide to Watching Beelzebub Anime Dub Episode 1

If you find listings for an English dub online, they are typically fan-made projects (fandubs) or international dubs recorded in other languages (such as Spanish or French) that have been mislabeled.