"Earth Emperor Dragon" Velgaia「"地帝竜" ヴェルガイア, "Chitei Ryuu" Verugaia」formerly ”Chaos Dragon" Gaia「"
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.
During Leon and Yuuki 's battle, Yuuki summons the Chaos Dragon that was previously sealed by Millim. Upon it corroding everything around them using Chaotic Breath, Leon quickly seals it with a Holy Attribute Barrier that is much stronger than the Hero's, Infinite Prison, but not before Yuuki has stolen its dragons' core (power) and becomes a Dragon Warrior. Yuuki is now covered by the same miasma that once covered the Chaos Dragon, resembling an ominous black armor resembling scales. Without its core, all that is left of the Chaos Dragon is bones and ash. Even with Yuuki's increased strength he is worthless before Leon's might and loses an arm. In this beaten state, he escapes before he is fully engulfed.
Inside the Red Knight, two souls were found by Rimuru and company. One was of the Red Knight herself and that of the Chaos Dragon, which has now been purified by Leon's previous attacks. With Rumina's help, the two souls are separated and the Red Knight is revived with the core of the dragon being placed into a jewel in the keeping of Rimuru, however, in doing so Gaia's power was greatly weakened.
An egg is formed from which Gaia is hatched and Milim is overjoyed. Since it was too soon to have him train with Millim; she, Rimuru, Veldora, and Rimiris proceeded to level up Gaia in the Labyrinth.
Gaia later combines with the dragon core of Zero and evolves to a True Dragon. As Gaia becomes Veldora's younger brother, Rimuru named it "Earth Dragon Velgaia."
After the Tenma Great War, Velgaia helped protect the Sky Castle by using his newly obtained Unique Skill All Creation Manifestation, which is a skill similar to Ramiris Labyrinth Creation, since Dagrule was sealed and could no longer act as the Gatekeeper.
- Rimuru - He has an affinity and affection for the slime. He is very friendly towards him.
- Milim - His best friend and companion. He loves Milim and she loves him.
- Velzado & Velgrynd - Velgaia is the fifth True Dragon to be born and thus is the younger sibling to Velzado and Velgrynd and since his birth was noted to be constantly doted on and spoiled by his Elder Sisters due to him being their new youngest sibling.
- Veldora Tempest - As Velgia is the fifth and youngest True Dragon to be born, he is the younger sibling to Veldora. And due to him now being the new object of affection of his two elder sisters due to him being the new baby of their family, earning the slight jealousy of Veldora who was the one previously dotted on by their two elder sisters as their youngest brother.
Gaia can absorb the surrounding magic power to build up its own power.
- Chaotic Breath: A miasmic breath that corrodes.
- All Creation Manifestation: To Be Added Later.