You should think about actually watching the cutscenes and what they say to each other during the fight.
Like "This is not what I wanted" or "What is this, Ascian?!", or maybe "We'll talk about it later".
Gaius wanted to rule and conquer, not destroy everything using Ultima >.>
I'm quoting Lahabrea, when he's talking with Gaius.
Lahabrea : And so it shall, for the Ultima Weapon is host to a power of which your are as yet ignorant.
Gaius : Speak plainly, Ascian.
Lahabrea : The Heart of Sabik. It is the Weapon's core. An enigma whose surface even the vaunted scholar of ancient Allag failed to scratch. The magick within has laid dormant for eons.
Gaius : Of what magick do you speak?
Lahabrea : A spell without parallel... Ultima. I sought the life force of the primals for no other reason but to quicken the core.
Must I continue?
