So all of the Titanic Watchers that were stationed in the Stormpeaks were in Uludar, obviously not counting Loken, because, well we killed him in halls of Lightening, with the exception of one. Tyr, the watcher symbolic of Order and Justice, whose myth inspired the name of the Knights of the Silver hand.
There's a quest where Thorim has you survey the different Watchers' towers, including Tyr's where you're told that there is no damage, and no sign of a struggle, as well as the guardians that should have been there being absent, with no signs of what happened. You're left to question where he is.
Fast forward to Patch 3.1, when we set foot in Ulduar for the first time, with the goal of freeing the Watchers from their enslavement and send the old god Yogg-Saron back to sleep. We meet all of the Watchers there, Minus Loken, whose death we caused with our own hands, minus one. Tyr is no where to be seen, and there is no mention of him anywhere to be seen. In addition, Yogg-Saron has a minion of a type never seen before, a lobster looking fellow by the name of General Vezax, who served as the last obstacle in your way before you engage His unholy mouthness himself.
Popular spectulation was that this new minion was in fact the corrupted and perverted Tyr himself, spectulation that blizzard quashed by saying that Tyr was not in Ulduar when Yogg-Saron was defeated. Or did they?
Let's look at their exact wording. They said that "Tyr was not in Ulduar when Yogg-Saron was defeated."
And where was Vezax when Yogg-Saron was defeated? Lying face down on the floor of his room. He WASN'T in ulduar. BECAUSE HE WAS DEAD :P