There's a slow nod from Even at the suggestion. He hadn't really begun to think about the hows and whys of their creation, but it makes sense. A less violent - or less strong - heart might well affect what sort of Heartless was created after the initial loss. They've never really had the best data on Heartless creation and he's not so sure he wants to try figuring it out anymore. Not now that he's had more of a change to see them in action.

"It's certainly plausible. If a person were less then accepting of their own strength it could certainly affect how they thought of themselves in those crucial last moments."