Gaia

Gaia (ガイア), formerly known as the Chaos Dragon (混沌竜), is the pet dragon given to Milim by Veldanava.

Background
Veldanava used the last of his energy to gift his daughter a pet dragon, in the hopes that she wouldn't be lonely. After Milim became orphaned, the pet dragon remained her only close family, and the two lived a peaceful, uneventful life together. These times didn't last long, however, as they became the target of a certain elven kingdom led by Jahil. In her rage, Milim wiped out the kingdom for killing her friend and awakened as a True Demon Lord. The gifts from her Harvest Festival brought the corpse of her dear friend back to life, but because its spiritual and astral bodies were severely damaged, it was resurrected in a corrupt state. It became a force that transcended both good and evil. In her sadness, Milim sealed her former friend away to end its destruction.