He is a creepypasta, he’s fictional. Honestly, I don’t know why people make up minecraft winning the hunger games that they’ve seen him, or heard him, or seen signs or buildings placed by him. I have seen HEROBRINE in Minecraft Pocket Edition, versions 0.
I’ve seen my sheep being dyed gray, instead of white. I built a cow pen after the first version of 0. There was a cow in it. I left the game, and logged back on.