User blog comment:The Crazy Terror/PE Proposal: Herobrine/@comment-1705775-20190730060459

Herobrine is a case of "depends on writer" - common to many folklore and urban legends, a good way to maybe have this character reviewed in future is to specify a specific story of Herobrine.. since he is like Slender or any other "stock character" these days.. some versions of him will count, some will not.

for an even better example take Dracula, there have been so many different stories that not all can be PE (some are barely even villainous) - so find the nastier portrayals of Herobrine and suggest them (beware of shock stories however as they also become auto-disqualified).

TLDR: Herobrine is more akin to a stock-character now and thus can only be PE in certain stories, not as a singular character.