Celestial Spirit Magic
Astral Embodiment (実施星, Hoshi Jisshi) is a special Magic which compliments Celestial Spirit Magic by allowing the caster to take on the traits of certain Spirits in combat. While the caster receives the magical energy signature of the Spirit, the two creatures do not fuse, but the Spirit is instead sent back to the Spirit World and the caster will take their place. This allows the caster to summon more Spirits while maintaining the abilities of the other Spirit. Due to the fact that it is limited to Celestial Spirit Mages, like the spell Urano Metria, there are rather few users of this Magic. To compensate, just about any Celestial Spirit Mage can learn how to use it.
When using this Magic, the caster is required to summon one of their Celestial Spirits in order to activate the Magic. Any Spirit can be used, as long as the Spirit belongs to the caster, even something as pathetic as a Nikora. However, in order to achieve a successful transfer of abilities, the Spirit must have a lower total magical power than the recipient. Extraordinarily powerful spirits, like Aquarius, are seldom compatible with the caster and the result would become rather lackluster. However, this still very much depends on the caster and Golden Keys are still valid candidates for transference for some users. The process of transfer itself is surprisingly simple in comparison to Magic similar to Astral Embodiment, as all is required is the consent of both the caster and the Spirit. This process does not work based solely on verbal agreement, as both parts need to be thoroughly committed to the transfer of power, both emotionally and verbally, as their magical powers need to temporarily synchronize. If in discord, the transfer will fail and the Spirit will be expelled into the Spirit World temporarily. However, if both parts consent, they will start glowing in the color of their respective magical energies. As they start to synchronize, the caster's magical energy will gradually start changing color into the one of the Spirit. When the two energies match completely, the Spirit will fade away into golden dust and return to the Spirit World.
Upon completing the transfer, the caster now temporarily possesses the exact abilities of the Spirit and can use them freely in junction with their own. If the Spirit utilized a medium for Holder Magic, the caster often gains this item as well, although the caster can use an item which they traditionally use in combat as a medium as well. However, some items are incompatible with certain types of Magic. For instance cannot the Spirit Scutum's ability be reliably used to full effect with Seika Goeiki's traditional weapon, which is a bow. On the other hand, the Spirit Sagitta is very compatible with her bow and it is therefore unnecessary to replicate Sagitta's medium (which incidentally happens to be its body). When the powers and abilities of the Spirit is transferred to its caster, the caster possesses the ability to summon more Spirits while possessing the powers of the Spirit. Even if they only possess the capacity to summon one Spirit at the time, the Celestial Spirit Mage can still summon a new one, as the previous Spirit is technically in the Spirit World, even though their power lingers. This provides a massive advantage to the caster, as they now can now make use of multiple Spirits' abilities simultaneously. Most notably, however, is the fact that the caster now gains the ability to defend themselves in combat. Due to the fact that the majority of Celestial Spirit Mages are relatively defenseless without their Spirits, this is a major boon in their favor which enables them to fight alongside their Spirits.
Although rare, there are occasionally some side-effects associated with the transfer. Occasionally, the caster will take on some of the traits of the benefactor, but only if the Spirit has a very strong personality. These traits seldom manifest noticeably, with the exception of some slight changes in temper. With the exception of the items the caster may receive to use the Holder Magic of some Spirits, there are also no physical changes associated with the transfer. However, the caster's magical power is in turn altered. Having become identical to the benefactor Spirit's, the recipient can technically disguise themselves as the Spirit to sensor Mages, as they are virtually indistinguishable from the Spirit itself. However, this does only lasts for the remainder of the transfer and the recipient's magical power will revert back to their own. The duration of this Magic depends on the individual Spirits and therefore also on the spells. Some Spirits are far more durable than others and therefore provide more long-lasting effects, while others exhaust far quicker. While this generally depends on the kind of key, some Silver Key Spirits have demonstrated that they are far more durable than even some Golden Keys and it is therefore a generalization to state that Golden Keys are superior in every aspect.
- Embodiment: Celestial Spirit King (施星：星霊王, 'Seireiō): When Akihito replaces The King, he gets his ability to stop Time. However Akihito isn't skilled with this ability, so he rarely replaces The King.
- Embodiment: Dreina (施星：ドゥレイナ, Jisshi: Dureiena): When Akihito replaces Dreina, he can use Mist Magic, every skill stays the same, except Clone (Arthur's clone can use exact same moves as him).
- Embodiment: Rose (施星：ロズ, Jisshi: Rozu) : When Akihito replaces Rose, he can use Wood Magic, Plant Magic and Flower Magic. However, he is able to turn into petals and reform after some time.
- Embodiment: Charta (施星：チャルター, Jisshi: Charuta) : When Akihito replaces Charta, he can use Paper Magic. However, he can replace her only for a short period because of her immense strength.
- Embodiment: Scutum (施星：スクトゥム, Jisshi: Sukutumu): When Akihito replaces Scutum, he gets her shield, but can't change its state. However, he can change the size of the shield.
- Embodiment: Rexus (施星：レクスス, Jisshi: Rekususu): When Akihito replaces Rexus, he can use Command Magic alongside Doll-Play Magic.