The Kaleesh spawned from an ancient colonization by the Falleen on their planet. Cut off from their home planet, they slowly adapted to the new environment, becoming more robust, and growing a pair of tusks. Then the events of the Great Kaleesh Oppression took place, when millions of Kaleesh were enslaved by their insectoid planetary neighbors, the Huks, and they fought back. After years of violent, bloody war, the Jedi brought a halt to this conflict. Then, to make sure this would never occur again, a Jedi attempted to erase all memory of this conflict, against direct orders. He succeeded in making the Huk forget, but was killed before he could erase the memory from the Kaleesh. Since then, there have been dozens of wars between the two species.