So I ran a Magic roleplaying game by straight-up tacking Magic: the Gathering onto FATE. We had a good time.
I should’ve stopped at bridging the gap between FATE and Magic: the Gathering, but I didn’t. This thing is a sprawling, 32-page document that creates a new set of Magic concepts and systems which absolutely do work as roleplaying background, but are fucking impenetrable. But hey, it’s 17k pages so I’m gonna share it with folks.
Moxes The real conflict in creating a Magic RPG is making the cards work in a roleplaying setting. I did that by instituting a set of power tiers–called moxes–which allow spells to scale in power with the planeswalker (or creature) casting them. The five moxes (relevant table on page 18) allow spells to scale. In the lowest mox–Mox Alpha–most spells take on a benign form. Tapping down a creature can make them drowsy, a burn spell can provide light, and a creature might become confused or addled if you make “an opponent” discard a card. At Mox Unlimited, a planeswalker can cast spells which annihilate whole armies. Those scales of power can also be applied to creatures, allowing bigger creatures to be massively more powerful than smaller ones.
Non-Combat Casting The FATE integration isn’t that strong, but one place where it works is non-combat casting. Five skills (Will, Investigation, Deceive, Rapport, and Athletics) are aligned with each of the five colors. Instead of spending a Fate point to invoke an aspect for a skill check for one of those five skills, a planeswalker can discard a card of the corresponding color. All they have to do is describe the spell they’re casting (it doesn’t have to be related to the card) and the aspect they’re invoking.
The Tempest This is the biggest concept to rationalize the randomness of a player’s deck. Planeswalkers channel/are a flow of aether which they can control by shaping it into spells. When a planeswalker runs out of ways to turn their tempest into spells, they must revert to Mox Alpha (the weakest mox) or die by decking out. The primer incorporates similar descriptions of almost everything, from the three ways to summon creatures to using artifacts and what even planeswalkers and emblems are.
Fetters Fetters are optional because they’re a bridge too far. They exist to explain some planeswalkers having higher “starting life” and to give players reasons to connect to planes. As a planeswalker’s maximum mox grows higher, they can connect part of their essence to a great project/thing. Fetters are represented by additional health boxes and act much as a phylactery for planeswalkers (but hopefully with a little more drama).
That still doesn’t cover Slow Casting, Planeswalker Stunts, or the general setting/NPC roster stuff, but I think it’s the high points. I’m especially proud of the three-page “Life, the Multiverse, and Everything” appendix at the end which conjectures on how planes are formed.