Qo'noS is home to the tlhIngan (Klingon) people and the capital of the Klingon Empire. Though Qo'noS is a class M world, its highly tilted axis contributes to extreme seasonal changes. As a result, its native life forms are aggressive and adapted to deal with rugged terrain and harsh environments.
- “Bringing Down the House”: Players must track the warp signature of Tarsen's warbird in the Qo'nos system to discover where he is going.
- “Blood of the Empire”: Players must close Fek'Ihri portals and defend a Klingon station in Qo'nos orbit.
- “Surface Tension”: In early 2410, the Undine attack the Sol System. After Rear Admiral Tuvok exploits an attempt of telepathic espionage by "Dr. Cooper" to his own advantage, he and the U.S.S. Voyager assist the player in defending the actual main target of the surprise attack: Qo'noS. Being initially hidden by the Praxis asteroid belt, joint Klingon-Federation-Romulan forces prevail and Tuvok takes part in the subsequent negotiation of a cease-fire between the Klingon Empire and the Federation in the Great Hall of the High Council.
- “Gateway to Gre'thor”: Players must repel a Herald invasion force.
- “Brotherhood of the Sword”: Players engage Herald ground forces in First City.
- “A Day Long Remembered”: The final battle of Qo'noS takes place and the player, along with their allies, charge into battle against J'mpok's flagship and his forces in orbit. They disable the Kri'stak following a failed attempt to destroy the player with a mycelial weapon, who swiftly moved to the K't'inga's position instead which allowed Tarsev's Elachi forces to surprise and aid them in battle. Just as the Kri'stak is disabled, the Targ enters orbit and J'Ula orders Adet'pa and Kagran to lead the fight against Aakar and his fleet while she beams down with the player, Martok and L'Rell to finish J'mpok.
- “Remain Klingon”: While battle occurs on the surface, a team of Alliance forces coordinated by Adet'pa, Kagran and Martok, who beamed up after being wounded by Aakar, work to destroy the Targ and the Kri'stak. L'Rell, having received Chancellorship, ceases hostilities and announces the end of J'mpok's reign, calling all warriors to return to the Empire without vengeance befalling them.