Tali'Zorah nar Rayya
Tali'Zorah nar Rayya is a quarian character in Mass Effect. She joined Commander Shepard in 2183 to aid him in tracking down Saren Arterius and averting the Reaper invasion of the galaxy. She returned to the Migrant Fleet for a couple years and acted a special agent for the quarians before rejoining Shepard in 2185 to investigate and defeat the Collectors.
When Shepard was taken into Alliance custody following the Aratoht incident, she returned to the Migrant Fleet again. She attempted to organize fleet preparation for the return of the Reapers and was given the rank of Admiral for her expertise, taking her father's seat on the admiralty board. She opposed the fleet's attempt to retake Rannoch from the geth, mostly because she considered the risk too great.