Faustian deals

I made a deal with Connor's desire demon... wait, I actually intimidated it and forced it to leave while giving me an information about blood magic. That's... not exactly Faustian.

In general, no. I usually kill those things. But I have to admit, they have awesome voices.

As for Connor - wiki says he doesn't appear if he's alive and possessed.

You can intimidate it?  Is that only available if the player character goes in?  Cause I sent Morrigan and that option did not come up.

If I remember correctly, yeah. You have to play as a mage Warden and have high enough Intimidation score (I don't know how much. I usually max out Coercion before doing any main quest after Lothering).

I bargained with Kitty. And then killed it. CG, not LG.

A lot of good answers. The reason I originally asked is because for a moment I almost let out the Demon that possessed Sophia. I kinda felt bad for it at the time. I know it's a demon and I killed a bunch until that point , but I almost let it go. In the end I killed it anyway and did not think about it after. This was the first time I almost made a deal with a demon in this playthrough. I did though make a deal with the demon that possessed Connor to learn blood magic, but that was years ago.

My second mage managed to scare it enough that it promised to leave; I think I must have done it with a high Coercion skill since with her build and the fact that I hadn't done the Circle yet there's no reason I would have had any strength to speak of. But then I failed the higher DC to intimidate it into giving me one of the rewards too, and its denial displeased me, so demon died.

I dealt with the demon in a more dickish, but mutually productive, manner with my first mage; he sold Connor for blood magic. I can't tell you whether or not he appears in Redcliffe if you do that, though, since I did CotJ when I imported that world.

And I think I must have let the desire demon in Broken Circle keep its templar a few times, but I can't remember how many.

And I let Sophia Dryden's demon live at least once, in the same playthrough where I sold Connor. (If you're wondering, I kinda went out of my way to be a dick in that one.)

(I also let Imshael live in that world-state, but I'm not sure if I'm supposed to count that one given that this is in the Origins section of the forum.)