Omega Leonidas (オメガレオニダス, Omega Reonidasu?) is the only existing evolution of Leonidas in the Bakugan video game. It evolves to defeat Battle Ax Vladitor, staying as the player's Guardian Bakugan even after fading upon Vladitor's defeat.
Omega Leonidas, being the player's Leonidas in its evolved state, now has two large horns protruding from its muzzle, one smaller than the other, while two horns just off its eyebrows, giving it an appearance similar to Neo Dragonoid (even though the Bakugan Video Game is set in the original Bakugan series). Spikes run along his back and tail. Leonidas's general color scheme is set in various color tones based on its owner's customized attribute. Large claws on its three-fingered hands and two-toed feet make even Leonidas's body a valuable weapon.
In the final battle with Marduk, Vladitor had evolved to become Battle Ax Vladitor. To counter his foe, Leonidas evolved into Omega Leonidas via the energy of other Battle Brawlers's Bakugan. As Omega Leonidas, it is a level 3 but at some points, it is at level 2. After the battle, both Leonidas and Vladitor faded out of existence.
Both Marduk and the player are saddened by the loss of their partners; however, the player reunites with his Guardian Bakugan at the fountain in the Park, where they first met, through the last strength of Battle Ax Vladitor. It was then that the two vowed to be partners for as long as possible.
- Omega Eraser: Has a different effect depending on the game version:
- Adds 200 Gs to Omega Leonidas. (Nintendo DS)
- Adds 400 Gs to Omega Leonidas. (Wii)
- On the Nintendo DS version, G-Power boosts for every Attribute on Omega Leonidas' Gate Card is 200 Gs, despite the card picture in the store saying otherwise (before you buy it).