The apprentice.

"Bran, you've got to stop questioning the Master like that during training!"

Bran slumped onto his pillow. "I know but I see how those threads weave together, the shapes they form. I know those spells can be improved and I will improve them."

"Just, please be careful. Please?"

"I'm always careful, you should know me better than that."

Extreme sadness in his eyes, the wizard watched the conversation play out five more times before sealing the room away forever.

"Fools. They never listen."