Sometimes you already do face 3 of them, Felosophy can be discovered from Illidari Studies.
Edit: You can always remove the Demon tag too if that’s a problem. That’s helpful in a couple ways. And while we’re at it, I think Raging Felscreamer should be a demon so you can’t stack the discount. Someone pulled out a 4 mana Inquisitor on me one game and I’m salty.