Mass Effect & Mass Effect 2
Humanity has encountered many galactic species. Wars have been few, but mistrust is rife.
Polticially, the Alliance is a peaceful trade partner of the TURIANS. As a practical matter, however, there is simmering antagonism and bigotry between both populations over the First Contact War of 2157.
The Alliance enjoys good relations with the ASARI, though many privately believe the Matriarchs are aristocratic and overcautious.
Though humans know better than to unconditionally trust any SALARIAN, their shared restless, reckless ways make them natural allies against the conservative turians and asari.
The KROGAN have no unified government, but individuals are generally treated as potential criminals, a reputation most krogan enjoy living down to.
The Alliance has no formal contact with the QUARIANS. Their migrant fleet has not yet passed through any human-settled system.
The batarians are rivals for control of the Skyllian Verge. They severed their treaties with the Citadel to prosecute a colonial conflict against the Alliance. Officially, there is no war, but neither is there any peace.
Mass Effect 3
- The text offered in the Codex changes based on what choice the player made in Mass Effect. This text is used if you choose Captain Anderson to serve on the Council.
A political-economic pact for collective colonial security, the Alliance is the central galactic institution of human society. The Alliance gained associate membership to the Citadel Council in 2165 and full membership in 2183, with Ambassador David Anderson representing humanity.
Human political-economic relationships vary between combative and lucrative. The turians who'd fought humans during the 2157 First Contact War have become valuable trade partners, despite residual social hostility.
Other relationships are even more complicated. The rapid rise of human political influence on the Council--achieving in decades what others waited for are still waiting centuries to acquire--has galvanized suspicion and resentment against humanity. That negativity is vastly outweighed by the respect and trust humanity earned by saving the Council during the 2183 attack on the Citadel, at the cost of the Alliance cruisers Cairo, Cape Town, Emden, Jakarta, Madrid, Seoul, Shenyang, and Warsaw and their 2400 crew.