>>96163496It's its own proprietary system, which will eventually be released setting agnostic called Plotweaver, but for now Cosmere RPG is the only thing using it.
It's much different than D&D, which is entirely class-based, and instead uses paths, which are skill trees that you're expected to go down multiple of, especially since you can't start off as the really cool paths that give you powers.
It's a D20 system with the caveat that in certain situations you also roll the plot die, which can give an opportunity or complication, and rolling a crit also gives you the associated resource for that roll. It should be noted that the sides of the die with complication on them have numbers, which are bonuses to the roll, meaning you might succeed where you wouldn't otherwise thanks to the bonus, but there's negative repercussions, such as hampering your allies.
One of the most impactful mechanics in terms of combat is the graze, where with some attacks you can spend focus (the nonmagical power resource everyone has) to still connect on a miss, dealing only the damage die without any of the usual bonuses.
The turn order is also unique; each player each turn calls either fast or slow, and then take their turns in this order: fast players, fast enemies, slow players, slow enemies. Fast players can take two actions, while slow players can take 3. Some actions take multiple action points to use, including some especially powerful ones needing 3, necessitating either another ability that increase the amount of actions points for that turn or for that player to choose slow if they want to use that ability. Players don't have a set turn order besides that, allowing for more strategic collaboration, and you don't have to declare your speed until you actually take it, so if a player going fast flubs in some way that necessitates someone taking a slow action to fix it (such as needing an extra action to do something) then they can change it on the fly.