The Heart of Sabik

[Viridiana]

When Gaius says "Lahabrea, what have you done?", this makes me believe the Weapon did not previously come with the Heart and the Garlean's simply threw it in after excavating and repairing it without a second thought because Lahabrea said so.

I took it more as a "There's something odd going on here! What have you done?" I assume that Gaius can tell Lahabrea is taking control of the Weapon, and can probably even feel it preparing for Ultima. I also took Gaius's "This isn't what I wanted" after the final battle as a sign that he preferred a clean conquer to a messy destruction, and Ultima certainly doesn't fit into that plan.