Reaper War

Military action

The Reaper War was a short-lived but incredibly destructive conflict waged by the Reapers against all organic space-faring species in the galaxy. The Reapers' intention was to carry out the latest of a cycle of mass extinctions of all technologically advanced life; this cycle was seemingly broken when the Crucible device, constructed by the species allied in mutual self-defense, utterly destroyed the Reapers with a massive energy blast.

Before the Reapers appeared in the Milky Way, they conducted several attempts to sabotage the galaxy before their arrival. The human colony of Eden Prime is attacked by the geth, initiating a wider conflict between humans and geth known as the Eden Prime War. After exposing the involvement of rogue Spectre Saren Arterius in the attack, Commander Shepard and the crew of the UTF Normandy pursue Saren in his search for the Conduit, later revealed to be part of a larger plan orchestrated by the Reaper Sovereign to return its kind to the galaxy. While Shepard follows Saren through the legendary Mu Relay to the Conduit, Sovereign and a geth fleet assault the Citadel. Shepard defeats Saren and the Federation Navy destroys Sovereign, preventing the release of the Reapers.   One month after the Battle of the Citadel, the UTF Normandy is attacked and destroyed by an unidentified assailant, resulting in the death of Commander Shepard. Later, the United Terran Federation officially declares Shepard "killed in action".   Commander Shepard is revived and tasked by the Illusive Man to investigate the mysterious disappearances of entire human colonies in the Terminus Systems. Investigation of the attacked colony of Freedom's Progress reveals the enigmatic Collectors from beyond the Omega 4 Relay to be responsible for the disappearances. After assembling a capable team, Commander Shepard uses a captured Reaper IFF to safely traverse the relay and infiltrate the Collector base. Shepard succeeds in eliminating the Collector threat, saving humanity throughout the galaxy from certain destruction.   September 21: A massive influx of batarian ships in the Exodus Cluster reported by the Federation News Network. The newcomers claim their home systems are under attack from an as-yet unidentified hostile adversary. Khar'shan is reported to be under bombardment and the Harsa relay blockaded.   Six months after the destruction of the Alpha Relay, the Reapers invade the galaxy through batarian space and attack Earth. Commander Shepard escapes and discovers a Prothean superweapon design on Mars that could end the Reapers' threat once and for all.   October 5: Hierarchy offensive to retake Taetrus reported as failed: four turian fleets dispatched to the Mactare relay, Reaper ships emerge from the Trebia relay in a push toward Palaven. Primarch Fedorian alerts the galaxy to prepare for spotty communications due to destruction of comm buoys during wartime.   To build the Crucible and take back Earth, Commander Shepard and allies embark on a journey to unite the various races in the midst of a galaxy-wide war. During the final confrontation with the Reapers over Earth, the Commander fires the Crucible, unleashing a galaxy wide energy blast that destroyed the Relays and any Reaper associated technology.