I think the conversation between Adar and Halbrand made me believe that Halbrand isn't Sauron and is either a potential Ring Wraith or the King of the Dead. Mainly Adar mentioning some child or love that he killed. And the reaction from Halbrand there made me think he hit the nail on the head.
I'm leaning towards the King of the Dead as the writers will want to give him some redemption story as he's pretty likeable right now.
I'm leaning towards the King of the Dead as the writers will want to give him some redemption story as he's pretty likeable right now.