This article describes characters who appear in the Mass Effect fictional universe and who have some conception and reception information.
The Mass Effect games take place in the 22nd Century. In 2148, mankind discovers an alien artifact on Mars that shows that humanity had been the study of an intergalactic species since the Cro-Magnon period. Research of the artifact, in addition to providing new technologies for humanity, led to the discovery that Pluto's moon Charon was really a "mass relay", an alien construct that is capable of transporting any ships faster than light to a nearby mass relay on the galactic scale. The mass relays work by creating a "mass effect", the production of dark energy from a reaction with Element Zero, to slingshot spacecraft to the next relay; Element Zero is found to also react with biological entities to give them "biotics", limited powers that evoke the mass effect on a much smaller scale.
On Earth, the Systems Alliance was formed to safeguard's humanity as it expanded to new colonies through the mass relay. Roughly ten years later, humanity made its first contact with one of the other alien races, the Turians, which erupted into the First Contact War. Though casualties were small on both sides, the war was interrupted by the Citadel Council, members of three alien races that oversaw maintaining peace in the galaxy. Humanity was then welcomed into the collective group of aliens, and learn that the artifacts, mass relays, and the giant station that serves as the seat of power in the galaxy, the Citadel, are all remnants of the Protheans, believed to be a progenitor race to all alien species in the Milky Way but have since disappeared.
The Citadel Council welcomes humanity into the Citadel, providing them with a Systems Alliance embassy and allow human members to join C-Sec, the Citadel Security forces, despite other alien races having waited for such a privilege for some time. As the newest race to join the Citadel, humanity tends to be looked down upon by other races, but the Citadel Council soon invites a human to become part of the Council and another to join the Spectres, elite enforcers that use both espionage and force to complete their assignments. On Earth, there is concern about how humanity is treated by these other species, and pro-human groups, seeking to pull humanity out of the Council at any cost, begin to appear.