Mass Effect 2 Edit
In 2185, Kal'Reegar and a dozen of his Marines accompanied Tali'Zorah vas Neema to the planet Haestrom, a former quarian colony now under geth control. Reegar's forces were tasked with the protection of the science team as they examined the strange nature of the system's sun, but most of the Marines were slaughtered by a company of geth troops, leaving Reegar as one of the two survivors of the task force.
Later, a squad of quarian marines attempt to clear the small science ship known as the Alarei after it is overrun by geth. However, they are unsuccessful, with every marine involved in the raid being killed.
Mass Effect 3 Edit
Sometime after the fall of Thessia to the Reapers in 2186, if the quarians survived their war with the geth and if Kal'Reegar survived Haestrom, Shepard will receive an Alliance News Network update stating that Reegar and his squad of Marines were killed on Palaven while repairing and protecting a critical communications tower used for relaying critical mission information back to the Turian Hierarchy.