。
Have you also been a wizard at some point, Edgar?
Literal
Edgar-san [topic-は] wizard was-[thing-事][also-も] exist [explanatory-ん] is [question-か].
A question built on the experiential ~たことがある pattern ('have done X / have the experience of X') with two small twists. First, こと is written in kanji as 事 — the same nominalizer, just a more traditional orthography. Second, the particle is も instead of が: ~たこともある ('have also had the experience of X'), implying that other past experiences are already on the table and this one is being added to the list. So the question isn't just 'have you been a wizard?' but 'among the things you've been, have you also been a wizard?' — picking up on a prior exchange. ~んですか is the explanatory polite question form, asking for confirmation or elaboration.