An idea I had from my pastor's sermon yesterday and fits well with a subtheme in the new set.
False Prophecy
TC Grey/Crimson EE
Place on your demon: If your evil prophet or heretic of the same testament as bearer is defeated, you may discard this to add bearer to battle. Cannot be interrupted if played in battle.
1 John 4:1 "Dear friends, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world."
Perhaps not the direction that we want to bring the game (with more evil battle extension), but it seemed a natural idea from the standpoint that false prophecy has demonic origins. It in itself is not orange, so you not only need to have demons to play it on but a grey or crimson character to play it from. Orange has a bit of synergy with crimson and not much with grey, so that's a bit of opportunity cost right there. I also restricted it to same testament in an attempt to prevent just splashing Abaddon/Dragon/Gates into a deck with Balaam and the new grey prophets (although the revelation stuff still works with heretics and the grey stuff works with KoT and the new Terrifying Beast).