Learning Magic

The player learns individual spells from their alien relic, and also from the other characters in their party. When a character casts a spell, the other characters in the party learn part of it. After seeing the spell enough, the other character can perform it. Once the player learns all the spells their relic holds, they can release the spirit of the relic to do a higher level spell. Each spirit can only be summoned by its original owner, and can't be learned by the other characters.

Each spell could have it's own quest/story/history to it.