Koshek

"Fuck (the other vorcha). Smart ones fall in line. Idiots die. Everybody wins."
Koshek is the current head of his tribe of biotic vorcha, having relieved his predecessor by shooting him in the head. He then successfully negotiated with Garrus Vakarian to trade the asari hostages the tribe had taken to acquire biotic training, as well as aiding the rest of the galaxy in gathering badly needed resources in hazardous areas in exchange for taking the offered place for all species on the Citadel Council.
Well spoken and pragmatic for a vorcha, the first agreement he made with Garrus was simple- "Don't make Commander Shepard mad."