Kirito

Kirito is the first generation Royal Tree ship of Azusa. Kirito means "Fog Seal."

Before Kirito chose Azusa, it was bonded to Mitsuki Amaki. Mitsuki had a special bond with the royal trees and could talk with Tenju and could learn the secrets of all of them. But she was sickly and was kept confined away from everyone else due to her ability. But she was lonely and upon witnessing Azusa being chased by Seto from her room, she set it up so he could come in and visit her. He came to care for her deeply until the forbidden access to her was discovered. The only thing left keeping her alive was the direct link to this tree and four others and she decided to let go of it so the tree would be free to choose him as its partner. She died almost immediately after witnessing the tree bond with him in his tree ceremony. He named it Kirito after a folktale she taught him, about the elements of the land loving the moon but only water could become fog and seal the moon away from the love of the others.

Mitsuki was then apparently assimilated by Kirito.