WN/Velgaia

History
Gaia has a long history as it originated as Star King Dragon Veldanava. After Veldanava died he was reborn as Gaia, who became Milim's pet dragon.

When her pet dragon was killed Milim was sent into a rage and ascended to a True Demon Lord and had to be subdued by Guy Crimson and Ramiris. When Milim evolved the Gaia's body transformed into a Chaos Dragon. However since it did not have a soul, the dragon transcended both good and evil becoming a force of pure destruction.

Milim in her sadness sealed Gaia's body away so that nobody could find it. However the dragon's energy slowly seeped from its body and ruined the surrounding nature. When the Freedom Association was asked to investigate the miasma, Yuuki found the Chaos Dragon.

Story
During Leon and Yuuki's battle, Yuuki summons the Chaos Dragon. Leon quickly seals it, but not before Yuuki has stolen its core and becomes a Dragon Warrior. Yuuki is still beaten in battle, but is able to escape.

Gaia's soul is soon found to be inside of the Red Knight. Rimuru transferred the soul into a jewel. However doing so greatly weakened Gaia. Ruminas then agrees to revive Gaia.

An egg is formed from which Gaia is hatched and Milim is over joyed. Milim and Rimuru proceed to level up Gaia in the Labyrinth.