Mandalorian–Ithullan war

Several Mandalorian warrior clans engaged the Ithullan species in a war over a narcolethe distillery in the year 200 BBY. After claiming victory over their foes, the Mandalorians proceeded to initiate the near extinction of the Ithullan race in what a number of galactic scholars viewed as the most heinous crime of its era. In retaliation, a group of rogue Jedi Knights allied with the Gen'Dai bounty hunter Durge, against the orders of the Jedi Council, and assassinated the ruling Mand'alor, leader of the Mandalorian clans, nearly a hundred years later.

The genocide of the Ithullan species led to a large number of Mandalorian soldiers growing dissatisfied with their out-of-control, immoral contemporaries. This desire for change was taken to heart by Jaster Mereel, who instituted a new standard of behavior for the Mandalorian warrior clans when he rose to the position of Mand'alor in 60 BBY, the Supercommando Codex, which stated that any Mandalorian who wished to fight were to conduct themselves as honorable mercenaries.