Sir Thomas is a living trashcan with magical powers. Though the versions Valor meets in The Stadium are hostile, the ones that serve as bodyguards for the king's minions can be found outside The Stadium and will not be hostile unless provoked.
Sir Thomas Van Scrap: (After reviving with Transient Heart) Computing… Move knight to E6… 33 seconds remaining… checkmate…
Sir Thomas Van Energetic: (In the western elevator) I'll take the stairs next time.
Sir Thomas has a normal and a corrupted variant.