Comment on Deliah Blue in Peril by Theo-Kyp-Serenno

It started during the mandalorian war when he was a jedi:

As the Mandalorian Wars continued, the desperate Republic military petitioned the Jedi Council for aid. Unwilling to charge into another conflict so soon since the last with Exar Kun and fearing a greater threat, the Council refused. Revan and his followers, however, did not. With the devastating details of the Battle of Cathar having become widely known—several years after the fact—Revan used them to his advantage. In an act of rebellion above and beyond anything he had ever done before, he refused to acknowledge the authority of the High Council and sent out a full call to arms to the Order. No longer was he arguing for Jedi intervention, he was going to intervene. As always, Squinquargesimus was the first to join his closest friend, but soon hundreds of Jedi answered Revan's call. An arrest order was issued for those Jedi Knights who joined Revan, and Squinquargesimus adopted the alias of "Malak" to avoid it.
Revan and his followers being confronted by Vrook Lamar.

When Malak returned from Coruscant to Cathar, Revan, Malak, and their Jedi were confronted by Vrook Lamar and a large group of Jedi, who surrounded Revan and his followers. It seemed as if their efforts would be for naught, as they would not be taken into custody. Revan, however, discovered something in the dirt - a Mandalorian mask. Suddenly, the group was beset by Cathar fleeing toward the ocean, followed by a swarm of Mandalorians. The Jedi ignited their lightsabers and tried to help the Cathar, only to discover that both the refugees and their pursuers were only vision of the past. This attack had happened years earlier, under the command of Cassus Fett. The Jedi watched helplessly as the Cathar were herded into the ocean and Cassus prepared to murder them all. One Mandalorian, however, flew to the Cathar and told Cassus that they had been defeated, and the genocide was unnecessary. Cassus declared that the Cathar must pay for dishonoring the Mandalorians during the Sith Wars, but if the warrior wished to speak for them, then so be it. Cassus saluted her efforts, then had the warships fire anyway, killing her and all the Cathar. It was this woman's mask that Revan had found, and after seeing this vision, he placed the mask on his head and vowed to wear it until the Mandalorians had been defeated once and for all.
Revan dons the Mandalorian mask for the first time and vows to avenge the victims of Cathar.

The entrance of Revan and his Jedi into the war marked its turning point. Revan's clever military strategies and tactics coupled with Malak's courage and fiery determination saw the pair becoming the foremost heroes of the conflict. Claiming victory time after time, they were propelled through the ranks of the Republic military and were eventually given direct control of a full third of the Republic's fleet. With his newfound authority, Revan spearheaded the Republic war effort and began to steadily push the Mandalorians back. Together, Revan and Malak liberated Taris, fought Cassus Fett—Mandalore the Ultimate's primary strategist—at Jaga's Cluster, and defeated much of the Mandalorian army at Althir. Yet, despite such victories, there were concerns raised over the Jedi's behavior. Though Revan's tactics were near flawless and Malak's righteous fury unmatched, the pair began to adopt very similar characteristics to the Mandalorians they were fighting, growing to despise weakness and indecisiveness in all its forms. Unfortunately for the galaxy, the growing darkness surrounding Revan did not just stem from his experiences with the Mandalorians.