I have played only once through in the thieves guild questline, didn't take the skeleton key to the sepulchre, question is, if I were to keep it again, how binding is the oath? Would Nocturnal be able to come into Sovereigngarde for instance and ask for the skeleton key, or is she not allowed in that realm? I thought it'd be kinda fun playthrough to do Darkbrotherhood and the Thieves Guild questline until it was time to take the key to Ebonmere, I am curious also, as I will have to study this, where did the skeleton key come from? Did Padomay give the skeleton key to Nocturnal, or did Nocturnal steal the key? I am assuming that Nocturnal stole the key, since she is the patron of the Thieves Guild, I thought it would be fun to go into Sovereigngarde with Lucian Lechance and the skeleton key, I feel in a real instance, in the aftermath of Alduin, you would be able to use the skeleton key to gain entry into the Hall of Valor once again, why is the door locked anyways afterwords? That is heartbreaking, because people like me, want to stay in Sovereigngarde Well, there is always Forgotten Vale, but still, it's kinda b.s. where Stuhn shouts you out (banishes) of Sovereigngarde, so what was the real point of going there? Sovereigngarde is supposed to be a type of Heaven right? It's like once you've done their bidding, they want nothing to do with you, bunch of drunken fools, if you ask me!

You can keep the Skeleton Key as long as you want. The only downside is you won't be able to advance the Thieves Guild to the final stages without turning it in.

Note, there is a Perk that offers the same advantage as the Skeleton Key, so you don't have to keep it all game if you want an unbreakable lock pick.

daedra cant just freely enter 'Sovngarde'