so i was just watching some lore videos and something struck me. so when sylvanas was killed by arthas and raised into a banshee against her will and forced to kill her friends and family, she swore vengeance on arthas. she later got said vengeance and then offed herself. this led to her meeting the jailer, teaming up with him, and then all the following events.
given we have seen the jailer craft a mourne blade right in front of her, she surely knows the origins of frostmourne and the helm of domination. this means that the jailer, sylvanas' current ally, was the one responsible for her death, necromantic rebirth, and subsequent killing of said friends and family. i get that sylvanas is currently in a mood where she wants to turn the system on it's head thinking she has been given no choice in her life but why would she team up with the person who personally created her original unending hatred?
the only thing i can think of is that uther and devos started the creation of the mawsworn/forsworn before sylvanas offed herself (which is possible given that devos was turned before arthas died), the jailer then had devos take sylvanas to him instead of the arbiter, lied to her about everything, and sylvanas is only finding out now that the jailer caused all this. but even that doesn't make sense to me because sylvanas knew before anduin was kidnapped that the plan was to turn him to their side, willingly or not.
any insight on something i may be missing would be appreciated.