[Sten]

Hm, I think you're right, and I knew what happened but not exactly when. I knew he burst out of Xvim at some point, and assumed that had already happened considering Xvim's temple was closed as a joinable faction while Bane's 2 temples stayed open and nobody specifically pointed out that he was dead. But the wiki does say Bane's resurrection was probably caused by Tam, who performed a summoning that same night.

The temples to Bane were open during his death as well, as some Clergymen remained loyal to him. Though I think it was Cyric that granted them spells during this time, I'm not 100% about it though.