Basically she was one of the titan forged created by the Keepers (the Keepers created by the Titans of course) who helped battling the Old Gods. I always been a fan of Titans lore let us hope she will get a big role in Legion.
From what I read in the wiki (didn't play beta so not sure) that she is the final boss of the Maw of Souls and escapes before she is killed.
I HOPE! Blizzard indeed make her escapes instead of killing her off in the release version of the game. I really don't want another Kargath Bladefist v2 treatment in WoD where he was suppose to have this awesome epic role in surviving the Highmaul encounter and fight us again in Farahlon raid patch content then boom they scrapped that awesome idea because of whatever reason (time maybe or something like that).