3 day after Halo 4, Blue team is sent to I03 to investigate te dissapearance of the SII unit Black Team, who they find dead. They proceed to to the site where the composer was foud and find the composed essences of the New Phoenix residents, as well as a portal to the composer forge. Once there, they encounter the Didact, and several more composers. Thy proceed to fight the Didact, but ultimately end up defeating him by jettisoning the section of I03 with the Didact on into the nearby planet, causing him to be composed by the Conposers.
In Spartan Ops, 6 months later, the UNSC and Jul's Covenant engage in several engagements throughout Requiem. The scientist Glassman is captured by the Covenant, and Halsey is brought to infinity to assist in research. an attack on infinity gets halsey captured by Jul, cauing ONI to olce an execution order on her. te same Librarian Essence that John encounters ends up co reacting Halsey, and gives her the two halves of the Janus Key- an Artifact that can reveal the precise locations of every Forerunner construct in the Galaxy. Lasky doesn't want to assassinate Halsey, so sends Fireteam Majestic to rescue Halsey after Palmer goes to kill her, with both units meeting up at the same time- Thorne gets one half of the Key while Jul takes Halsey, after she is shot, with the other half. The series ends with Jul sending Requiem into it's sun, and escaping with Halsey stating she wants revenge.

Several weeks later, peace talks between the Arbiter and one of the Brute clans led by chieftain Lydus begin on the JOZ of Ealen IV; the meeting is mediated by Hood and Lasky; however the talks are attacked by another Covenant group led by Vata 'Gajat; it is revealed there is a traitor amongst te UNSC in the form of Spartan Scruggs. When Infinity makes its way back, it is attacked by Vulture gunships and Sparrowhawks with identifiers of the Spirit of Fire. Later investigation leads the true mole in the UNSC to be Captain Clayton: James Cutter's son. As the Infinity prepares to find the SoF, all they find is a Covenant station that proceeds to use a glassing cannon to nearly destroy Infinity. However, Clayton is captured and revealed to be part of the New colonial Alliance, stating the insurrection has agents on every world and that the UNSC will come crashing down very soon. The final page of said comics reveals the Spirit of Fire to e evacuated with several flood infection forms running round the abandoned cryo bay.

The UNSC has since continued to engage in minor conflicts with smaller covenant groups, up until Atkis, a planet covered in ocean apart from a single plateau with a Forerunner structure and inside, a slot the exact gape of the Janus Key. The UNSC sends forces to investigate the site only to be ambushed by Covenant; it is at this point it is revealed Jul's covenant is splintering with a sub group believing Jul is a heretic- this group led by Sali 'Nyon ambushes the Spartan team and takes the other half of the Janus Key from the UNSC.