Kal'Reegar is a soldier of the migrant fleet and is part of the team sent with Tali'Zorah vas Neema to the former Quarian colony of Haelstrom in the far rim. Shortly after Shepard lands on Haelstrom it is revealed that the Quarians were attacked by Geth. Shepard first meets Kal'Reegar taking pot-shots at a Geth Colossus, at this point the player must confront the Geth platoon and has the option to tell Kal'Reegar to stay down and give him/her covering fire while the player attempts to flank the Colossus. After the Geth platoon is taken care of and the player rescues Tali Kal'Reegar will enter the room and inform them that their ship is still in working order and he is able to return to the migrant fleet without aid. At this point Tali will tell him that she is not returning and is instead going with Shepard.
Note: It is possible for Kal'Reegar to die in the effort to rescue Tali.
It is possible for Commander Shepard to meet with Kal'Reegar again on the Flotilla if the player chooses to complete Tali's loyalty mission. Kal'Reegar is one of the few Quarians that does not believe the allegations against Tali, and in fact holds her in high regard. Kal'Reegar can be brought in front of the Admirals as a witness on Tali's behalf if necessary. It is also possible for Shepard to ask Reegar about his thoughts on the Quarians plight and how they might reestablish a homeworld. Reegar states that while he believes a full on war against the Geth would be futile and would likely damage the Migrant Fleet he would never shy away from his military duties.