Yea, this episode was just truly horrifying.
It's odd, since I know a bit more about the character from the comics. So I see what they're doing, but I can't tell if they're going where the comics went, or if they're just going in a different direction.
Spoilers below (out of respect)
So in the comics, David has hundreds of alternate personalities, each one fully controls a different aspect of his powers, but in the show they're talking about a parasite inside him instead. Not sure if they're going to be incorrect about the parasite or if they're changing it up. However, that scene from an episode or two ago of David screaming in the astral plane with dozens of other unknown characters yelling at him kind of hinted at the comics way of doing things.