Some worldbuilding thoughts that randomly came to me, so now I must write them down. Subject to change, etc., but I think I like this.
Spirits can be bonded to mages, bonding a Spirit is really the graduation exam for every mage.
Spirits do not bond to spellcasters.
A Spirit can only be bonded to a single mage, but a mage could be bonded to multiple Spirits.
There is a mark that appears on both mage and Spirit which indicates their bond - haven't decided what this looks like yet, but I am thinking either a ring on a finger (yeah, I know), or a mark on the forearm. This second is pretty interesting to me, as Gwen has her as covered, and most Spirits have short sleeves. This may also work with the asymmetrical sleeve design on the Ri Spirit. Hmmm.
Symbols are standard for all mages (so another Ri mage would have the same marking as Gwen)
The Four Spirits appear on one side of the mage, and the Two (Gai and Tas) appear on the other.
These symbols are also how people can recognize a legitimate mage (if the staff and sphere were not obvious enough)
Once bonded, Spirits are linked to the human until they're either released by the mage, or the mage's death. In theory, the Spirit's death would also release them, but that is an unlikely scenario.
Bonded Spirits can be summoned at any time, and maintain a kind of background connection to their mage.
Major Spirits cannot be bonded. Minor Spirits can. The Lesser (Duf, Phi, Roh) Spirits cannot, as their allegiance is only to their Major.
