Occupying a hostile colony on the outer reaches of Citadel space turned out to be a logistical nightmare for the Turians, who believed winning Shanxi had succeeded in crippling the humans' military forces. After a series of battles, the Turians broke through and managed to siege and occupy the planet of Shanxi, the closest human colony to Relay 314. One human spacecraft escaped the initial attack by the Turians and fled to warn the Earth Systems Alliance, which launched a retaliatory strike against the Relay 314 aggressors. Related: Mass Effect: How Player Choices Affect Garrus' Personality This attack escalated into what humans call the First Contact War Turians refer to the conflict as the Relay 314 Incident - to them, it was nothing more than an act of law enforcement. The aggressors were the Turians, a regimented alien race that filled many security roles under the Citadel Council and were merely stopping the illegal activation of a dormant Mass Relay.

In 2157, while reactivating a Mass Relay known as Relay 314, a group of human explorers was attacked. Eager to explore as much of the galaxy as possible with the newfound mass effect technology, humans wantonly reactivated dormant Mass Relays and colonized new star systems. Humans began exploring interstellar space after discovering Pluto's moon, Charon, was actually a Mass Relay entombed in ice. Humanity's first interaction with an alien race proved violent, turning into a short but intense conflict known as the First Contact War. Prior to the events of Mass Effect 1, many of the other races who dwell on the Citadel had been traveling the cosmos for thousands of years already. The Mass Effect games depict a complex and highly advanced galactic civilization, but at the time of the first game, humans had only been a part of the interstellar community for 26 years.

Mass effect human ships