Professor Pappas was the father of Melinda Pappas and friend of Janice Covington. He was the 1924 Nobel Prize winner of Anthropology and graduated from the South Carolina University. He was an archaeologist who specialized in deciphering ancient languages.
Janice Covington sent him a telegram, asking for his help in searching for and ultimately deciphering the Xena Scrolls. When he died in 1941, his daughter Mel found the telegram and went along to help Janice instead. Like his daughter, Professor Pappas also went by the name "Mel Pappas," but it is unknown if Mel was his full name or if it was short for something, just as his daughter went by Mel instead of Melinda.
If Professor Pappas is a direct descendant of Xena, then he and his daughter must be a descendants of Eve, the reincarnated soul of Callisto, since Xena's only other child, Solan, died before he produced children of his own.