William is beloved by his men and commands extreme loyalty from them. He has a calm, friendly demeanor and nearly always wears an amiable smile when conversing with other people. He still maintains a somewhat mysterious aura due to the fact that most of his expression is covered by his mask.
He is an observant, cautious individual who quickly noticed Asta's high athletic ability during the exam, and who also attempted to keep the other captains in check during Geldor's attempted escape by pointing out that the other man may be under the influence of someone else's magic.