The Draka one plays during the introduction to the house of champions. As @
Valysar mentioned one does play in Bastion as well when dealing with the memory shrine there, and maybe I got that wrong, but I thought the fallen Kyrian there was a different one than the one in the clip, which is why I thought it wouldn't fit there.
- - - Updated - - -
No, the ones dying there are Blizzard and your ilk. Also my post clearly lined out that this kind of "RPG element" has never been part of WoW before, hence why I tackled everything that was remotely similar, because this exact case has never been seen before. I even gave you a list of other RPG elements that would actually signify a return of said elements to the game, because betting all on this one system is not going to do what you guys think it will do, hence your collective delusion of RPG grandeur that just isn't there. All you do is make a bad descision that limits your potential for no gain what so ever and you somehow have bought this BS that this is the one and only way to bring RPG back; a rather narro(minded) definition of RPG if I may say so..
And you definitely are locked. While can somewhat easily catch up on other covenants, it is still an incredible amount of extra work compared to just having your character progression as it should usually be. Not to mention that once you cycled through once you can only switch on short notice if you happen to do it near the weekly reset, as otherwise you will have to wait for up to 1 full ID and what ever time you need after the reset. All that just so that you can have fun with the obvious PvP covenant ability in PvP instead of your AoE one form your M+ build, because this game is still an MMOrpg.