From Halopedia, the Halo wiki
- Insurrectionist forces of the United Rebel Front unsuccessfully attempt to invade and occupy Draco III's rebuilt capital of New Albany, resulting in a prolonged standoff between themselves and the UEG. Standoff results in the death of all insurgents but at least one UNSC soldier who was being held hostage was killed.
- An incident occurs on a space station operated by the SPARTAN-IV program as a training facility, beginning with the murder of Spartan-IV trainee Hideo Wakahisa by fellow Spartan candidate Rudolf Schein, now working as an agent of the United Rebel Front. Schein subsequently attempts to destroy the station with explosives, though Musa-096 and Jun-A266 are able to stop him; however, Captain O'Day is killed in the process, while Jun and Schein are propelled into space through a breached viewport. Jun is rescued on time by Lucy-B091 and Tom-B292 while Schein is left to die in the vacuum of space, with the three Spartan-IIIs receiving medical treatment for several days for their vacuum exposure.
- Shortly after Schein's failed terrorist attack, Tom-B292 and Lucy-B091 are reassigned from their duties as Spartan-IV instructors to serve under Franklin Mendez as part of the security staff of the Onyx United Research Project on Shield World 006.
- UNSC Rubicon arrives at the ruins of Installation 00 and deploys several remote contact teams (RCTs) to the Ark's surface.
- After 8.3 days, all contact with the RCTs is severed, after being attacked by the installation's fauna and constructs. Only RCT-06 returns to the prowler, having suffered extensive casualties. However, they bring the source of the signal aboard: the remains of the monitor 343 Guilty Spark.
- After properly calibrating their AI translator, the human team began to interrogate Spark, hoping to gain insight into the ancient human-Forerunner relations and the Didact. Spark, acknowledging the humans as "the true Reclaimers" proceeds to describe the events that led to his former human self becoming a monitor.
- After Spark finishes his story, his robotic shell powers down and is jettisoned into space by order of the ONI team commander. Having successfully uploaded his data stream into the ship's computers, however, Spark disables Rubicon's AI and takes full control of the vessel. Having come to the conclusion that the Librarian is alive as a result of long study, and that he has need for the ship and its crew, Spark puts them to sleep and sets course to where he believes the Lifeshaper could be found.
- Bobby Kodiak, the only survivor of the RCT Broadside, is "saved" and converted into a cyborg by 000 Tragic Solitude after surrendering himself to the AI.
- Dr. Catherine Halsey, working on Ivanoff Station, files an audio log regarding the discovery of the Composer on the nearby Installation 03 and is fascinated by the similarities between the Forerunner device and the UNSC's AI matrix compiler.
- Jul 'Mdama and his followers find the shield world Requiem. They attempt to gain entrance to the shield world but are unsuccessful until 2557.
- The Battle of Draetheus V takes place as Covenant forces under Merg Vol attack Draetheus V. The battle sees significant losses on both sides and Draetheus V itself is nearly destroyed when Merg Vol's activates X50. The main hostilities conclude with Spartan Sarah Palmer killing Vol and sabotaging X50's main weapon, bringing the Covenant's quest to a halt.
- Some time after the battle, the Covenant return when a looping Forerunner code begins emanating from X50. After arriving at the source of the signal, Spartan Palmer discovers that the source is the remains of Spartan Edward Davis.
- The Concord incident takes place, involving the use of outer-plated Mjolnir armor legs by Spartan-IVs.
- A recolonization support fleet of the UEG arrives to Alluvion, discovering a strange anomaly under the planet's Sundark Sea; Forerunner shield pylons, which emerged and forced back massive walls of water revealing the seafloor.
- Fathom Station is commissioned by Imbrium Machine Complex and designed to locate the crash sites of Splendid Intention and UNSC Of Uncommon Courage.
- The Gladius-class corvette UNSC Sagan Blue and the twin Kig-Yar-helmed storm cutters Mark of Prophecy and Divine Breath engage each other near New Carthage.
- The F-41E Broadsword enters service with the UNSC, featuring several improvements over the original F-41 Broadsword.
- Jessica Shea's twitter: Today in Halo 1/3/2554
- Halo: Fractures, "Lessons Learned"
- Halo Waypoint: Catalog Interaction - Page 14
- Eleventh Hour reports, Report #4 Provenance
- Halo: Hunters in the Dark, pages 5-8 (Google Play edition)
- Halo: Primordium, pages 11-13
- Halo: Primordium, page 371
- Halo: Primordium, pages 376-379
- Halo Mythos
- Halo: Nightfall, ONI: Trade Barriers
- Halo 4, campaign level Composer, Audio log
- Halo Waypoint: Halo 4 Terminal: Jul 'Mdama
- Halo 4 Interactive Guide
- Halo: Escalation, Issue #7
- Halo Waypoint - Catalog Interaction (Page 43)
- Halo: Spartan Assault, Battle at the Arid Sea
- Halo: Spartan Assault - Mission 30: The Source
- Halo Waypoint - Jordan Gaines
- Halo 4, Outer-plated legs description
- Halo Waypoint: Alluvion
- Halo Waypoint: Fathom Station
- Halo 4
- Halo Waypoint - Canon Fodder: Stay Frosty
- Halo: Warfleet, pp 28-29