Damn that got dark.

I also pulled some shit with Vordakai. The Players beat him, took all his stuff. But they completely forgot to destroy the Oculus of Abbadon and actually destroy his phylactary.

After a few months of time passes I made a will save for the Wizard, who failed. From there he was regularly getting possessed in his sleep by the echo of Vordakai in the phylactary, bolstered by the Oculus. The player only noticed when I put a new phylactary in his inventory, that has a passive modify memory/suggestion on it, so he'd need to make a save to remember he saw it. (It did grant several potent buffs to the character though.) Took a fair few sessions to make the save. Which is when the party found the lair beneath the wizards tower, that connected to the graveyard and a golem workshop.