Arca Jeth, first earned legendary status during the Hyabb-Twith Campaigns, a series of battles between the Jedi Knights and the Nelori Marauders of Dachat. Arca Jeth was one of the Jedi who pursued the Nelori to their main base on the planet Voon. The group of Jedi destroyed or damaged much of the Nelori base and ship fleet, however, the Jedi were driven back, taking heavy casulties. More Jedi soon came as reinforcements and infiltrated the marauders stronghold. Arca, searching with the Force, discovered the Nelori deep within the depths of the planet. During their search, the Nelori attacked Arca and the other Jedi in full force.

Thinking the Jedi had no chance of victory, and feeling helpless, Arca abandoned his Jedi training and increased the ferocity of his attacks. However, as he witnessed the course of the battle, Arca put his trust back into the Force and offered it an image of victory he had in his mind. At one with the Force, Arca had changed the tide of the battle by allowing the Light Side to sweep the battlefield strengthening Arca and his fellow Jedi. The Jedi were victorious, and Arca took it upon himself to completely rid the Corridor of the remaining Marauders. Decades later Arca became a Jedi Master, proficient in the art of Jedi Battle Meditation.

Arca Jeth became the watchman of the Onderon system and set up a training compound on the world of Arkania, attended by many Jedi Padawans and Jedi Knights. Perhaps his most famous apprentices were those of Ulic Qel-Droma, Cay Qel-Droma, and Tott Doneeta. It was during this time, training Ulic, Cay, and Tott, that Arca was asked to go to Onderon to end the civil war between the inhabitants of the walled city of Iziz and the barbaric beast riders.