Herobrine Persson is a urban legend and the titular main antagonist of Herobrine, a creepypasta created in 2010 that was based on the video game Minecraft. After gaining popularity thanks to a streamer, he spread throughout the Internet and appeared in countless mods, maps, story arcs, fanfics, videos, theories, songs, webcomics and books, becoming so popular that his existence was acknowledged by Mojang, even making cameos in some promotional artwork.
He is an enigmatic figure by nature, with his character, motivations and backstory are not explicitly defined, but following official descriptions from the original Creepypasta, this entity could be Notch's dead brother somehow embedded into Minecraft who appears as an omnipotent and malevolent ghost, although Notch stated that he never had a brother. He is commonly portrayed as a horror villain to many people.
Herobrine has become somewhat of an icon in the Minecraft community: despite having no appearance in vanilla Minecraft, he has appeared in many forms of fan-made medias, most commonly in YouTube videos. He can also be found in some promotional artworks by Mojang.