In toying with the idea of Planeswalkers with ETBs instead of static effects, we started by templating Davriel off of Ashiok's Erasure. Bouncing him puts the spell back on the stack like Spell Queller, creates a powerful control combo with Teferi, Time Raveler, and allows for stealing spells as Davriel does in the lore.

Nice, finally a Dav that actually captures what he does. Should it maybe only hit instant and sorceries or non-creature spells for balance?

I considered making it noncreature, but I feel like that would not be powerful enough for a Mythic. Similarly to Hostage Taker, the trick is to remove him before his controller gets the card advantage (like with a Bolt or combat damage). While his ability is more powerful, the timing restriction keeps it in check. The 2 life prevents too much recursion, though this can be offset by building more around the card (as it should be).