Our initial idea was to have a single-faced card that went into your library and would fetch the double-faced card from outside the game when you cast it
Hes one of the mythics in the Intro decks, sat across from Sephiroth
Avacyn, Guardian Angel can even help raise your white devotion count to get the most out of cards that need devotion like Heliod, Sun-Crowned
As players are shuffling their main-game libraries to form their subgame libraries, they should set aside the cards they wish to have on the subgame battlefield as the subgame begins
If that card was a Creature, it gets a +1/+1 counter on it, and you gain one life
Across multiple versions of the same characters, we see their identity evolve in a trading card game, just as we did years ago when we played the video games