Osika Kirske served as a Vollick military leader on the harsh world of Rattatak. Kirske orchestrated the demise of Jedi Master Ky Narec, while also taking Padawan Learner Asajj Ventress prisoner, compelling her to battle as a combatant within a brutal fighting pit located on Rattatak. However, he met his end at the hands of the Sith Master Dooku, who then recruited Ventress to become his Sith student.
During the era of the Republic, Osika Kirske held the position of a military ruler on the planet of Rattatak, where he maintained a private viewing box at a gladiatorial arena. In the year 23 BBY, Weequay marauders under Kirske's command subjected the people of Velenki, a settlement on Rattatak, to harassment. The Jedi Ky Narec, together with his Padawan, the former enslaved person Asajj Ventress, intervened to aid the villagers. Kirske threatened to set the village ablaze unless the inhabitants surrendered the two Jedi Knights into his custody. The villagers complied with Kirske's demands, yet the warlord proceeded to have the village set aflame regardless.
Kirske's Weequay raiders surrounded the two Jedi, firing upon and terminating Narec. Enraged by her Master's passing, Ventress retaliated against her aggressors, decimating the raiders as well as the Rattataki conspirators who had plotted Narec's murder, including Zol Kramer and Rynn'k-lee. She eventually overthrew all of the planet's warmongers and took their place, claiming the world as her own. However, Kirske lured Ventress into an ambush during her attempt to assassinate him, using himself as the point of the trap. Ventress was captured and forced to fight in a gladiatorial arena. During one of Ventress' fights, the Sith Lord Dooku visited the arena in search of an executioner, watching Ventress from Kirske's viewing gallery. Choosing to take Ventress as his Sith student, Dooku used his lightsaber to behead Kirske, thus ending the warlord's life.
Osika Kirske, a member of the Vollick species, was a ruthless warlord who derived pleasure from watching his enslaved gladiators engage in combat. Despite promising the villagers of Velenki safety in exchange for Narec and Ventress, Kirske broke his promise and burned their village, disregarding their agreement.
The first mention of Osika Kirske within the new Star Wars official storyline occurred in the 2019 audio drama Dooku: Jedi Lost, authored by Cavan Scott. Within the Star Wars Legends expanded universe, Osika Kirske made his initial appearance in the 2004 comic book titled Republic 60.