I think the problem lays elsewhere. The problem I think, is within the structure of the society that has been built. Inevitably, two Titans will clash and the resulting battle all thought of what they fight for will be lost to the rage of battle.
A third wheel no matter how small, would pivot balance, simply by one destroying the other. In doing so will weaken itself. Allowing a third party to covet the voids.
Just a thought.