I feel like they made Omega to omnipotent to be the final boss of this content. It would be to difficult to defeat him directly but it may be possible to beat him by straining it's resources.

Since it seems so adamant about finding a foe within lore/fantasy to defeat the Warrior of Light, the last arc may involve a chimera of different fights to test out how strong the Warrior of Light is to the point that Omega throws everything at you causing it to leave itself vulnerable to attack.