Atherton Wing was a young nobleman on Persephone who, when he appeared in the episode "Shindig," had hired Inara Serra on multiple occasions and was eager to enter into a more permanent arrangement with her. At a fancy ball, he accepted an unwitting challenge to a duel from Malcolm Reynolds after Mal struck him for treating Inara like a whore (despite his own frequent and blatant insults to Inara in that very vein, Mal justified this action on the grounds that he only disrespected Inara's profession, while Wing's comment and actions showed disrespect to Inara herself).
Wing was known on Persephone as a master swordsman who had won many duels. Mal could barely swing a sword. Wing toyed with Mal throughout the duel and nearly won; just as he was about to, however, Inara begged him to spare his opponent. This distracted Wing long enough for Mal to disarm him and win the duel.
Duels on Persephone are apparently always to the death. Not killing your opponent brings great shame upon him, and that is exactly what Mal did. Furious at his humiliation, Wing threatened Inara with physical and professional harm as she departed with Mal, swearing that she'd never work again. Inara curtly informed him that in reality, he was the one in trouble: Wing now had a black mark in the Companion's Guild books and would never be able to hire a Companion again. Sir Warwick Harrow added the rider that he would therefore be forced to fall back on his personal charms to attract women, which the older man seemed to view as a bad bet.
Behind the scenes
Atherton was portrayed by Edward Atterton.