<P> Lasky gives Fireteam Osiris the aim of finding and capturing Blue Team . Osiris is deployed to Meridian to pursue Blue Team, where they find a human colony under attack by Promethean forces . During their pursuit, they encounter the Warden Eternal, a Promethean serving as Cortana's enforcer . After temporarily defeating the Warden, Osiris catches up to Blue Team, ordering them to stand down and return to Infinity . Blue Team, instead, board a Guardian: large Forerunner constructs built as enforcers of entire worlds . Osiris barely escape the colony's collapse as the Guardian activates and disappears . The Guardian emerges on the Forerunner planet Genesis, where John and Cortana reunite . Cortana says her terminal rampancy was cured by the same Forerunner technology that saved her . </P> <P> Osiris is deployed to the Sangheili homeworld of Sanghelios, where they plan to use a dormant Guardian that resides there to travel to Blue Team's location . However, the planet is engulfed in civil war; the remaining forces of the Covenant have chosen to make their last stand there . To hurry their mission, Osiris joins forces with the Arbiter and help him strike a crucial blow at the Covenant remnant . Osiris boards a Guardian with the help of Commander Palmer while the Arbiter finishes off the last Covenant troops . </P> <P> On Genesis, Osiris encounters the planet's caretaker, the artificial intelligence 031 Exuberant Witness, who allies with them to stop Cortana . Osiris catches up to Blue Team, who reveal Cortana is planning on using the Guardians to achieve galactic peace through forcible disarmament . Master Chief, aware of the massive devastation Cortana's plan will cause, attempts to convince Cortana to stand down . She refuses and confines Blue Team in a Forerunner prison, to prevent them from interfering with her plan . Osiris manages to transfer control of Genesis back to Exuberant, who wrests the prison from Cortana as she leaves the planet via a Guardian . </P> <P> Artificial intelligences across the galaxy begin swearing allegiance to Cortana and her plans . Cortana locates Infinity and prepares to disable it, but Lasky has the ship's AI Roland, who is still loyal to Infinity, engage slipspace away from Earth and commit to random jumps until they can develop a way to combat Cortana . With Blue Team recovered, Osiris returns to Sanghelios to reunite the SPARTAN - IIs with an injured Commander Palmer, Thel'Vadam, and Halsey . If the player completes the game on Legendary, an extra cutscene shows an unknown Halo installation powering up while Cortana hums, before cutting to black . </P>

What is cortana's goal in halo 5