Mass Effect: Blackwell

A recent addition to the galactic stage, Human society (called the Systems Alliance) advanced significantly with the advent of interstellar travel, made possible with the discovery of lost Prothean technology on Mars in 2148. The discovery that Charon was a Mass Relay encased in ice allowed for far reaching travel and rapid colonization. During this time, the Systems Alliance had continued to build up their military fleet and installations. They constructed massive military stations at the nexus points of the Relays.

Humanity continued to expand outwards and establish more and farther colonies on uninhabited planets. This fast expansion brought them into contact (and conflict) with the turians. The Human-Turian First Contact War of 2157 brought humans to the attention of the other species of the Citadel Council, who wasted little time in ending the war. They brokered a peace between the humans and turians and introduced the humans to the larger galactic stage with other alien races.