
Usually, people summon spirit animals that are native or common to their area/region. (In the Four Fallen's case, and the summoners of the Great Beasts in the second series, they already had names, due to them being Great Beasts). Their names are decided mutually between the spirit animal and the summoner. When summoned, a spirit animal is always an adult (Although a kitten appears in Broken Ground as a spirit animal) It can also be any gender.

The Bile successfully cured the bonding sickness, but it caused the human to be in total control of their spirit animal, and allowed Gerathon to take over the human or spirit animal's conscience and control them. The Bile was then created from the Jade Serpent of Gerathon the Serpent to serve as a substitute to the Nectar. The continent of Stetriol in particular was deprived of the Nectar, causing thousands of people to develop the bonding sickness and die.

However, drinking the Nectar did not guarantee a spirit animal, and many people did not have access to the Nectar in the first place. After the war, it was common for people to drink the Nectar of Ninani and call a spirit animal. Not much is known about spirit animal bonds prior to the First Devourer War. After the events of The Evertree, the bonding sickness was abolished as a result of the Evertree’s rebirth and the bonds form naturally at any time between 11-12 years of age. With the sickness came the gift of the Nectar from Ninani the Swan, a substance that is drank at a Nectar ceremony to safely summon a spirit animal. However, in the First Devourer War, the Evertree was damaged and people started to develop the bonding sickness. The bonds between spirit animals and humans is preserved by The Evertree.

Spirit animals commonly appear to/are summoned by a human of the age of 11-12. A Spirit Animal is a lifelong partner that is bonded to a human.
