DRK Trainer will end up being Papashaun's twin brother.

He left Ul'dah ages ago, not content with the Sultana's rule, and learned the Dark Arts to counter the code of the Paladin taught to the Sultansworn.

I haven't cleared 2.55 yet, but the patch note picture and certain peeps' context clues make me able to put together what happens somewhat, so it fits.