To avoid spoilers, do not read
The Knight is a minor but important character in Braid.
Role in the StoryEdit
He only appears in the game's final level, Braid, where he is apparently trying to destroy the Princess by summoning a giant wall of flames. As it turns out, the whole fiasco with the knight was in reverse: he was trying to save the Princess, and Tim was the monster that was after her. Of course, this was only in the "untrue" ending. In the true ending, he, along with the rest of Braid's denizens, succumb to the Princess' explosion, leaving only Tim alive.
The Knight could represent conscience, as, according to popular conception of what the game Braid is all about, that would prevent Tim from creating the atomic bomb. This is supported by the fact that knights are often depicted as brave, heroic, and, of course, saving princesses, making him the perfect antagonistic force that is keeping Tim from achieving his goal, which also makes the knight a symbol of doubt as well.