Battle of Cathar The Battle of Cathar was the second battle of the Mandalorian Wars before the Mandalorians invaded the Galactic Republic , as the Mandalorian Neo - Crusaders under the leadership of Mandalore the Ultimate conquered worlds just outside of the Republic space . It resulted in the virtual extinction of the Cathar species . It would later be the event that resulted in Revan ' s Jedi faction joining the war . History . Prelude . During the Great Sith War , the Mandalorians , led by Mandalore the Indomitable , sided with the Sith , led by Exar Kun and Ulic Qel - Droma . The Mandalorians ravaged many worlds under Qel - Droma ' s command . But the Cathar species were able to stand against the Mandalorians , and aided the Republic and Jedi in repulsing the Sith and Mandalorians . By the war ' s end , the Mandalorian numbers had been severely reduced . Mandalore the Ultimate , Mandalore the Indomitable ' s successor , rebuilt the Mandalorians by not just reuniting the surviving Taung s , but opening membership to other species . Under his leadership , the Mandalorians became stronger . When the Sith suggested they invade the Republic , saying it would be a battle that would be remembered forever , the Mandalorians eagerly agreed . To prepare for their invasion of the Republic , the Mandalorians began conquering planets outside Republic space . Meanwhile , the Mandalorians remembered the dishonor they had suffered at the hands of the Cathar during the war with Exar Kun . Because of this grudge , Cathar became one of their earliest targets . Cassus Fett , Mandalore ' s prime strategist , was assigned to lead the attack . Battle . The Mandalorians ' attack caught the Cathar people completely off guard . Their military forces converged from space , bombarding the surface , first destroying all interstellar communications relays and orbital spacedock facilities , and then descending to the surface and slaughtering most of the planetary population while they slept or as they fled . Cassus Fett ' s Basilisk war - mounts decimated the more primitive Cathar settlements . However , because they had stood against the Mandalorians in the past , the Cathar realized why they ' d " truly " been targeted , and that there would be no mercy for their species or their world in the end . And because the Cathar were not members of the Galactic Republic , they were left to fend completely for themselves . Near the end of the battle , Cassus herded the surviving Cathar into the ocean and ordered that they be killed . One Mandalorian objected , saying the Cathar had already been defeated . But Cassus said the battle was about revenge , and he intended to kill all Cathar on the planet . He then gave the order to have the remaining Cathar killed , and the Mandalorian who objected died with them . The final act of the Cathar race was to pack the last able - bodied survivors who were able to withstand spaceflight into what few ships remained , sending them off into the void as quickly as possible . Juhani ' s family escaped aboard one of these refugee flights , and landed on Taris . The Cathar species itself , though , was nearly rendered extinct as a consequence of the genocide of Cathar . Aftermath . The Mandalorians didn ' t stop their conquest with Cathar . They continued to conquer systems outside Republic space and eventually invaded the Republic itself . The Mandalorian ' s smashed the Republic military in numerous battles and were on the verge of completely conquering the Republic . The Jedi Order , however , refused to enter the war because the Jedi Council thought there was an unseen threat that was more dangerous than the Mandalorians . This changed in 3963 BBY . The Revanchist s , a group of Jedi who wanted to defend the Republic in the war , came to Cathar to find proof of the Mandalorians ' atrocities . The Jedi Council , which had recently dealt with another rogue Jedi faction , sent a team of loyal Jedi , led by Council member Vrook Lamar , to confront them and order them to disband . Soon after that , the Revanchists ' leader found a discarded Mandalorian mask . After this discovery , all the Jedi present then received a vision of the battle , proving the Mandalorians had virtually wiped out the Cathar . Outraged at what he had seen , the Revanchists ' leader , who took the name " Revan " , swore he wouldn ' t rest until the Mandalorians had been defeated . The knowledge of the battle proved to be the catalyst that convinced many Jedi to join Revan . The Council , meanwhile , sanctioned the Revanchists ' actions , but still discouraged other Jedi from joining them . After the end of the Mandalorian Wars , Cathar began to resettle their world and by the time of the Galactic Civil War , it had fully recovered from the damage the Mandalorians had done .