Mister Canon.
He pops up in a whole lot of different contexts. He's the guy who loudly corrects your portrayal of a Ventrue in Vampire, because according to the decisions of the Grand Convocation of the McKetrick Supplicants in the Seventy-Second Year of the Reign of Prince Pompinfuss, no Ventrue would EVER wear mismatched cufflinks.
He's the guy who shows up at conventions dressed in Jedi robes and prepared to lecture you at length about A-level, B-level, and C-level continuity, and to defend the Star Wars Holiday Special as an important and historical event.
He's also the guy who tells you that your Rashemeni wizard is completely wrong because, gee, Rashemeni wizards are always female, and besides, your accent is all wrong, it should be more Russian!
No matter what incarnation he takes, he seems utterly unable to grasp the fact that most people--even most gamers--just don't care as much about the minutiae of the setting which happens to be his particular obsession.