"Law did."

The undercurrent of anger (and the dark rolling sea that accompanied it) that had simmered under his explanation disappears almost instantly, replaced by something warm and proud (calm, steady blue-gray waves), even if he's still not going to smile about it. Law suffered a lot to free that kingdom and its people, to finish the task Rosinante started over a decade previous and failed to see through.

Rosinante isn't exactly aware that the weird water thing going on on his skin is apparently also something of a mood ring.

"Not by himself. He assembled allies. Took my brother and his entire operation down, and handed him and all of his followers to the Marines. Doflamingo will spend the rest of his life confined, restrained, in one of the lowest levels of the government prison. Alone, with nobody to feed his narcissism."

Thirteen years late, and he will forever kick himself for failing to follow up on Vergo's mission, for leaving Law too soon and leaving the kid with no outlet for his love but desperate, bitter revenge.