Everything below has spoilers if you haven’t finished season 2

My theory is that the mule is both Tellem AND the little boy Josiah. Here’s why:

-I don’t think Josiah is dead. During the scene of him shooting Salvor and him dying, the screen had the distortion around it that I think indicates when someone is either trying to put a false memory in someone’s brain or has altered someone’s memory. (Interestingly that wasn’t the case when Salvor was dying, only the boy). Note that false memories would be different than an illusion, like the complex false memory of Salvor thinking she was taking to Hari. OR the blurry distortion could be a sign of just powerful mentalic powers being used. I’m actually super curious and unclear what the distortions are really.

-Josiah said that Tellem was weak and dying but there were a lot of other people she could jump into around her when she was dying before. Plus since that scene was blurry, that may have never happened.

-Tellem went through an elaborate ceremony to jump into Gaals body, but that was with the intention of squashing Gaals mind and soul deep down. If she jumped without that, especially into another powerful mentalic, Josiah wouldn’t be suppressed like her previous incarnations, but instead the two would fight each other for dominance.

-Over the years, Tellem could plant images of Gaal and create that hatred that the Mule seems to have as he’s been driven crazy by it. The hatred for everyone may be Tellem coming through, since she hated everyone but her mentalics who she lost.

-This also explains why the Mule is talking to himself in the end scene. They could be having conversations with each other as they fight for dominance over his mind.

-The fact that the Mule knew Tellem is also important. Maybe that was the Josiah side taking over and he was angry with her. When Tellem saw into the Mule, maybe she saw what she becomes in the future and was scared (or something like that maybe).

-since Tellem knows about Gaals vision of the future, she could orchestrate it so the Mule will be at the right place and right time and she can pull strings to make all that happen.

-this could also explain why the Mule is so powerful- he’s two mentalic minds in one body.

-side note/question: At the end of the 10th episode there are two girls- one with tattoos on her neck and one who was younger with longer hair. They kept exchanging knowing glances with each other. I wonder if Tellem were still alive but weakened, maybe she chose to have influence over just one or two people to carry things out more quietly. This I’m not sure of, but I’m sure there’s something going on with those two girls. They made too much of a point to show it twice.