Burke's personal assistant and a talented apprentice mage working at the Erianne Institute.
You have no idea what Percival looks like – so far, he’s been obscured by a magical bubble. He paces a lot.
Fine, spoilers: He looks like that. —>
(He is often overworked.)
Certain secret correspondence found on the fourth floor of the Gatehouse indicates that Percival was in cahoots with a character known as Journeyman Jack. The two traded secrets: Percy kept Jack informed about what was happening in the Erianne Institute, and Jack used his influence over the Gatehouse’s quartermaster to dig up old records at Percival’s request.