Ghoul's, when they are summoned from hell, most likely do not have a name unless they had been summoned before then sent back. Ghoul's are nameless until their owner or summoner names them.
Usually most of the time, a ghoul is named after their element, or something to go with their element, but one ghoul named Sodomizer got his name... a much different way, even though it has nothing to do with the Fire element.