Charles Dupin took the surname of his adoptive parents, but his biological family were Honoré Delagardie and Philippa Drummond, who were killed in an accident some years after witnessing the Wold Newton Meteorite strike.
Charles's adoptive family suffered financial reversions, and went into insolvency; however, their creditors were sufficently genorous to allow his son C. Auguste Dupin to live a life of scholarly indulgence in his Parisian home, which position allowed him to develop a reputation as a ratiocinative thinker and detective (as made famous by Edgar Allan Poe).
According to the scholars behind the French Wold Newton Universe website, the surname "Dupin" is actually Poe's name for the "Lupin" family, and that Charles Dupin's mother had had an affair with her husband's (supposed) coachman Louis Lupin. According to this theory, Charles is also the ancestor of a notorious gentleman thief, as well as father to a brilliant detective. Charles's wife is identified as Amelie de Lagardère, a relative of the Delagardie, and they are credited with a daughter named Augustine who is said to have bore Nero Wolfe as son to Mycroft Holmes, a proposition that few Wold Newton enthusiasts would likely support. A more interesting idea is Vincent Mollet's cited theory that some of the cases ascribed to C. Auguste Dupin by writer Gerard Dole might actually have been adventures of Charles Dupin himself - or perhaps that they were, in fact, one and the same individual.