In the original Famicom Version of the game, it is the default job class, while in the Remake Version, it is a secret job class. It has very low statistics. After level 92, (not to be confused with job level) the Onion Knight gains 12 on each stat per level (on DS and iOS version). It is recommended to use the Onion Knight class after reaching level 99.
The four Onion Knights of the Famicom Version are not named in-game. The official manga serialization of the game, Legend of the Eternal Wind: Final Fantasy III, names them Muuchi, Doug, J. Bowie, and Melfi (the only female in the group). In the Dissidia Ultimania guide and on the series's 25th Anniversary website, they are given the same names as the protagonists in the Remake Version of Final Fantasy III - Luneth, Arc, Refia, and Ingus.