Timeline
22th century to 26th century on Interstellar history: Hiatus
2511: John 117 born
2517: John enlist as a SPARTAN II
2534: Steven Hackett born
2537: David Anderson born
2548: accidentally, Prothean data cache on Mars discovered by civilian excavation team. Traces of element zero and mass effect drive cache translated. It also contains info that Charon is actually a dormant mass relay. Earth and its colony panicked about ancient alien and contemporary alien. Discovery of alien was failed to cover by ONI, causing entire religion devolved into superstition. UNSC prepare full armory and massive fleet for possible future conflict. SPARTAN II program mass abduction continued.
2549: UNSC scientist unlocks Charon Relay. It's lead to Arcturus cluster, 36 LY from Sol and not colonized yet by UNSC. Later discovered that mass relay was enabling galactic travel. Following this, ONI reveal existence of Prothean but Forerunner doesn't. Any Forerunner artifact that found were excavated and confiscated by ONI. Human expansion boosted rapidly with relays. Arcturus became center point of military of Far colony. Usage of relays is faster than slipspace. Following this, Traces of other ancient spacefaring race also discovered and excavated. Xenobiology, xenoarcheology and xenotechnology became formal studies in university around UNSC space.
2552: Brute Rebellion erupt, Jiralhanae ranks demoted and bring back to the Covenant
2554: UNSC encompass 1000 worlds. Insurrectionist activity also increased rapidly.
Commander Sheppard is born
2555: Mass Effect field FTL successfully merged with Slipspace drive.
Project Mjolnir retrieved
2557: Turian caught human settler open dormant Relay 314. One from 350 known relays which forbid opening by Council law. Shanxi incident occur. 2 week after Shanxi occupied, UNSC Second fleet ordered by HIGHCOM to evict alien from Shanxi, arrived at Peking system. ODST, Marine and SPARTANS quickly crush occupier at planet surface. Citadel Council later intervene and brokering peace, reveal galactic community to humanity. Councilor Tevos order Turian apology and pay reparation to Shanxi to prevent genocidal campaign to Council races.
N7 Specops formed
2558: Cerberus formed as human showing their xenophobic as a party which highly devout to the Mantle.
ONI terms number 009-087-2558 is withholding of all Forerunner artifacts and restrict to shared with the rest of galaxy. Citadel didn't know existence of the Forerunner until Covenant told them.
2559: BaAT at Gagarin station were developed as biotic training and research as human aware of biotic potential
UNSC follow Unified Banking Act
2560: System Alliance was formed by HIGHCOM as sub governmental branch for Far Colonies. UNSC divide colony into 3 branches: Inner, Outer and Far. Far colony is colonies which settled via mass relays. Since 2549, ONI classified it as 3rd wave. Alliance Charter ensure that System Alliance exist as lesser government under UNSC HIGHCOM and CAA authority.
2561: UNSC develop SPARTAN III and Biotics company as preparation to war against Batarian and possible another alien. Biotic potential is recognized and biotic acclimation Station was constructed.
Citadel Council invited human to join galactic community with maintain an embassy in Citadel. HIGHCOM refuse after read terms and agreements which smelled "want to limit human movement".
UNSC Spirit of Fire Missing In Action
2562: Arcturus station construction finished for house of System Alliance Parliament.
2565: Citadel Council offer UEG a chance to gain embassy, HIGHCOM agree to maintain embassy as a friend not as client races. And they feel free with 200 years old culture which they do. Which mean that human can maintain embassy without bound with Farixen, Citadel Conventions, or Genetic act. Economic, cultural and scientific of both faction rocketed following years.
2567: Asteroid Campaign sparked against Insurrectionist at Attican Traverse.
2571: unofficial Batarian lesser hegemony, named Skyllian Dominion demand Citadel to give Skyllian Verge to Batarian as expansion for official Hegemony. Citadel which no dare to displeased humanity refuses and decline the petition. Batarian official then severe any diplomatic contact from Citadel and impose self exile and isolation on their space. Effectively they became rogue state.
2572: Shepard enlist to N7
2573: ONI Prowler corps open dormant relay and discover shield world 007
2576: Batarian Pirate, Slave lord and Mercenary attacking System Alliance semi-independent colony, Elysium. This attack named "Skyllian Blitz". Colony occupied with massive loss of material, personnel and data. Survivor report attacks to System Alliance which reports it to HIGHCOM. However, due diplomatic fallout with Hegemony, retaliations delayed.
ONI smell that Batarian help Insurrectionist.
2577: human colony, Akuze devoured by Trasher Maws.
Quarian elevated by UNSC
Shadow Broker- ONI wars, a war for information which hidden from public occurred
2578: HIGHCOM dispatch a massive fleet with a SPARTAN III company to all out war as retaliations on Elysium. UNSC defeat Batarian at Torfan, Effectively ending Batarian presence on Council space.
2582: Cortana presented by Doctor Halsey on Reach to Master Chief
As responsibility loss of shield world Oblivion, Thel Vadam branded with Mark of Shame and ascended as the Arbiter while survivor of fleet of Particular justice reorganized as Fleet of Retribution.
Prefect armor and Mjolniir GEN2 enter service
A Prowler dispatch to Geth space for survey
2583: event on Mass Effect 1 occurs. Geth, Rachni and Krogan under Saren Arterius and Sovereign attack The Citadel. UEG fleet fortunately can upset Saren's plan and thanks to Chief and Sheppard. Reaper invasion delayed, Councilor saved and humanity arose to high status in galactic public. However, still impossible human became councilor because impossible to have a leader if the Council race is not follow Citadel policies. However, David Anderson appointed as Citadel lesser councilor.
Steven Hackett appointed as Vice Fleet Admiral for assisting Lord Hood.
UNSC Infinity dispatched to service
ONI excavates a dormant Monitor and unknown species sample in shield world Hades. Its later known that species was The Flood.
"Storm" Covenant, a terrorist organization based on Hesduros formed by Jul Mdama after disillusioned from Covenant religion. Organization increase rapidly due incite.
2584: Collector made mass abduction. Mass Effect 2 occurs. Vigil, a copy of Vendetta and numerous Ciphers were confiscated by ONI. After learn intel that Crucible, Conduit, Prothean scientist action, Citadel, Mass Relays, Reaper, Indoctrination, Collector, Keeper and Sovereign also Reaper Cosmic Imperative, ONI warn HIGHCOM for possible invasion. UNSC perform mass mobilization. The mobilization is including SPARTAN IV and SPARTAN IVB program.
Rachni surrender to Council. Realizing that Rachni are useful, Rachni quarantined on a system. Rachni now serve as subordinate race to Citadel.
Grothan Pazness escaped from Hegemony and form Batarian Separatist. This Batarian now had an embassy on Citadel
Quarian Separatist broke away from Migrant Fleet and serving the Citadel. They regained embassy
Because their action in Facinus attacks on Oma Ker, Krogan Urdnot clan gain limited vaccine for genophage exclusively for their clan. They now serve the Citadel and maintain embassy.
2585: Mass effect news of 2185 occurred.
February, Covenant fleet, Righteous Interdiction wage war against Collector at uncharted world after Collector made several Elite and Brute abduction. Collector defeated and retreat.
18 February, Covenant fleet under Prophet Commands, Eternal Clarity opens a relay in Phoenix Massing. Lead to Isolated-independent colony, Velasia in Keppler Verge, Attican Traverse. Fleet sparks 3 month long guerilla war against Council races until caught by Council officials on May. A peace between Covenant and Council forged a week later.
13 March, a contact made between UEG and San Shyuum Stoic survivor. Covenant goes hot
September, event of Mass Effect 2: Arrival occurred. Project Base activated for delay Reaper Invasion at a cost, Bahak 300.000 residents vaporized with star, gas giants and relay.
Battle of X57 between Batarian Slaver and System Alliance
A supernova destroys Soell system and Installation 04. 343 Guilty Spark escape and search for reclaimer.
Covenant gain Hardlight technology due a data cache on shield world, it incorporated to projectile, shielding (barrier, gauntlet, armor) and sword also architecture
Arina scandal crisis begin, Tevos and Matriarch Aseia charged bribing Covenant 600 Asari Harlot. Tevos free but Aseia imprisoned on exiled colony
first Sangheili Biotic are born
film "Fall of Heresy", a fictional film which stared by Sangheili draw attention of the Covenant. later, it was approved due contain a propaganda against Jul Mdama Heresy.
Sparatus killed by Facinus Assassin
2586: event of Mass Effect 3 occur. On 20 February, Reapers invade galaxy through Vular System. Only several hours, Khar San fall, effectively dissolving Hegemony, Survivors head to Alliance space. Earth was most fortune can handle Reapers for a month before their fall on 17 March. Covenant, after know that Reapers who unleash the Flood long ago, declare Reapers as Abominable Heretic Intelligence and must wiped out. Thanks to Prothean and Forerunner intelligence, can modified the Crucible and thanks to Council, true cure for The Flood can be found. Sheppard and Master Chief fight through galaxy and unite organics and synthetics against a common enemy, Reapers. But Flood have break free from one of unidentified Shield world, Sanctum and made its way to Sol system. On battle of Earth they fight to break near endless galaxy fate and unstoppable abomination. Their decision on Crucible will change galaxy, forever….
Codex
Hades Shield world: a shield world which contain an unidentified dormant monitor and numerous flood samples.
Sanctum Shield world: a shield world which because a protocol fiasco cause major Flood outbreak. The Flood disrupts Unyielding Hierophant Luminaries and lures them to Shield world then break free.
Oblivion Shield world: a Shield world which described as a reliquary. Thel Vadam and his fleet arrive to excavate the shield world. However, due accident, Elites unleash the Flood. Covenant hesitates to glass the sacred world. Causing Monitor of the shield world activate fail safe protocol thus destroy shield world and Thel Vadam fleet.