A Dragoon Spirit (ドラグーンスピリット, Doragūn Supiritto) is the essence of a Dragon that emanates its power from a crystallized colored stone. It allows a being of its choice to become a Dragoon. There are only eight Dragoon Spirits in existence – specifically, seven (Fire, Water, Earth, Storm/Electric/Volt, Zephyr, Light/Divine, Dark/Shadow) original spirits and one new spirit, Viror.
When its previous owner dies in presence of the next owner, the stone glows brightly, rises into the air toward its new owner, and gently levitates downward to the latter. When the Dragoon Spirit does this, it is said to be choosing, or recognizing a prospective host.
In the case of bloodlines, it is much more likely that a Dragoon spirit transfers to someone close to its previous owner. The spirit will wander if no host can be found, eventually returning to be birthed as fruit from the Divine Tree.