I don't know. That's like saying that people can't be different from each other. It isn't the role that makes someone who they are.

[Roles are just guides. And they aren't always followed-- like how Aya isn't a typical princess. He's got such a simple way of viewing things. But maybe it's that he knows first hand. After all, he hadn't been a typical cowardly person, or so people say. He still doesn't think he's anywhere near as brave as Sigmund, though.]