Celestial Spirit Magic (星霊魔法 Seirei Mahō) is a Holder Magic and a type of Spatial Magic used by Celestial Spirit Mages that involves the summoning of Celestial Spirits. Celestial Spirit Magic is a type of Magic in which the user summons Celestial Spirits by opening their gates through the use of Celestial Spirit Gate Keys. These Keys are separated into two classes: the more common Silver Keys and the rarer Gold Keys. Keys for Celestial Spirits are counted in Units (collectively without regard of Gold or Silver), and a Celestial Spirit Mage is noted by how many Units they have obtained.
When a Celestial Spirit Mage receives a Key and opens its Celestial Gate for the first time, they have to set up a contract with the respective Spirit. This contract consists of asking the Spirit which days it can be summoned by its contractor. This simple agreement leads to a dedicated and serious bond between the Spirit and summoner. However, under certain circumstances, i.e. during battle, and a Spirit is summoned for the first time, the making of a contract may be suspended on a later date.
Contracts can be broken if the Mage gets arrested, releases the Spirit by themselves, or dies. When a Celestial Spirit Mage summons a Spirit, it appears directly next to them, as that's where the gates to the Spirit world had been opened. It's impossible to summon spirits elsewhere.
The Spirits must also abide by certain rules enforced by the Celestial Spirit King. The only rule is that a Spirit may not directly or indirectly kill its summoner under any circumstances. When the Gates are closed, it is required from both the summoner and the Spirit to agree upon the gate's closure. However, Spirits can also be "forced closed" in battle, which means they can be forced back into the Celestial World by the summoner's will, though not every Celestial Spirit Mage is capable of doing such. Celestial Spirits also have different categories of sorts that fall under the basic summoning conditions from their own (eg. Water for Aquarius).
There are 12 Golden Keys based on the 12 Horoscopes (If there are names it means the key is taken):
- Gate of the Water Bearer Key: Emilia
- Gate of the Golden Bull Key
- Gate of the Giant Crab Key
- Gate of the Maiden Key
- Gate of the Archer Key
- Gate of the Lion Key
- Gate of the Twins Key
- Gate of the Ram Key
- Gate of the Scorpion Key
- Gate of the Goat Key
- Gate of the Paired Fish Key
- Gate of the Heavenly Scales Key: Emilia
Each key may only be possessed by one person at a time. A non-celestial mage may be in possession of a key, however they may not use it. The abilities and appearance of a golden key celestial spirit, may be altered to please it's owner.