Duelist's real name (and secret identity) is Julia Dabney. She is a remote descendant of the flamboyant 17th century French opera singer Julie d'Aubigny. When Julia took a vacation in Provence, she touched a stone that marked the unlabeled grave of Julie d'Aubigny, and was infused by her spirit.

The present Julia Dabney is a fusion of who she was before, and Julie d'Aubigny. From Julie, she has gained immense self-confidence, crossing into overconfidence, a love of being flamboyant, and incredible fencing skills. Fighting villains while wearing a showy outfit was a natural fit.