Spirit Arts

Spirit Arts are techniques, which manipulate odo to impart one's will and desired image onto mana, causing phenomena that alters the world around the user. The reason why this happens is because mana itself has a vague sense of consciousness.

Summary
In the Seirei no Tami, the Spirit folk, who have a deeper connection to Spirits compared to Humans, practices Spirit Arts rather than magic to cause phenomena. Ursula, one of the three elders explained that using Spirit Arts requires one to manipulate their odo (life energy), or what Humans refer to as magic essence and imprints their mental image on the mana, which overflows in the world, resulting in various phenomena.

But, in the Yagumo Region, their residents used Spirit Arts rather than using Magic, being a common thing among their people compared to other places because of Ryuo, who taught it to those who couldn't use it.

Spirits
Spirits are benigs made of mana that, under miraculous circumstances, were able to develop their own consciousness. Spirits often materalizes in a wide arrange of forms to interact with others, most of them being animals and being separated into different classes ranging from Low, Middle, and High-Class.

They are noted as having extraordinary affinity for using Spirit Arts, in comparision to Spirit folk and Humans, befitting a technique meant to manipulate mana itself.

It is important to form contracts with Spirits, but this tends to be based on their own will. Once completed, Spirits tends to reside within their owner's body in spirit form, and materialize outside. For Spirits, their contractee acts as a source of odo, being the most comfortable for them to reside within.

Because of this, a contractee and Spirit can communicate with one another via a telepathic connection between them. In addition to this, forming a contact with a Spirit allows Spirit Arts users to utilize it to a different level compared to before, and of course a magnitude over than magic.

However, different from Animal-Type Spirits, Humanoid-Type Spirits, who're considered the Highest Spirit Class can such as the Great Dryas are able to communicate with others and hold proper conversations. However, in comparison to others, Humanoid Spirits are extremely rare to the point of counting their numbers using one hand.

Spirit Arts versus Magic
Spirit Arts is more difficult to learn compared to Magic, requiring one to detect, perceive, odo, and detect mana. It is far different from Magic, which require one to detect magical power (odo), and undergo a Contract Ceremony, which engraves a formulae in their body, turning it into an artifact. In other words, turning a natural being into an unnatural one, letting one cause certain set phenomena using chants and spells. Magic is much more easier to learn for Humans who has lower affinities for Spirits Arts.

Though difficult to learn, Spirit Arts allows one to cause more phenomena compared to those who uses magic, in addition to being possible without chanting and creating magic circles. These phenomena can also be controlled much freer than those using magic depending on the Spirit Art user's capabilities. To use Spirit Arts, one must not have a formulae engraved inside them and can form contracts with Spirits, natural beings born from mana who resides inside their host without turning them into an unnatural being.

Trivia

 * Rio suspects that the heroes use some kind of Spirit Arts. This is due to their Divine Arms activating without magic circles, and really no need to chant the name aside to make the image stronger, while Huguenot claims the heroes’ weapons are special types of magic weapons that can only be used by their registered hero. However, there is one key difference in the heroes’ methods with Spirit Arts compared to other users. The main difference is that Spirit Arts users feed their ode to Spirits while heroes feed it to their weapon, and the weapon will cause the phenomenon as the hero wills it instead of the user themselves.
 * It's different than a magic weapon that can only activate the magic that been inscribed into it.