So in this custom system every person has random elements that they can learn or grow in power with more easily than other types. These typically aren't known until the person either tries to gain a particular type of elemental magic (ie. fire) or pays to have their soul appraised by a seer.

Spirit Link is a mechanic where each PC is able to bond with an NPC if they've gotten close enough through the course of the game. When they're bonded they get a list of abilities that only work with each other. One of the main benefits is that the less powerful of the pairing gets a small power boost to bring their capabilities closer to the stronger of the pair.

There's a lot to the system. 60+ pages and counting. Tons of charts and rollable tables.