[Usa studies the number over Byleth's head, reaching out to put her hand through that one, too.]

You have the ability but don't know how to use it? Most I've seen requires imagination or willpower. I'm not sure what kind of theories are involved.

[She reaches up again to the number over her head, pretty stable now. Her hand passes through with no change.]

What could it possibly want? We figured out how to make it stop changing.