Collector General

The  Collector General  was a unique Collector who controlled the rest of the Collectors from the Collector Base. Like all Collectors, the General was a victim of Harbinger's indoctrination up until its death at the hands of Shepard and the Commander's squad

Attributes
The General's physical appearance was quite different from the standard Collector, which has a humanoid shape. It had a more insectoid appearance, with a larger head, a short body, and multiple limbs, enabling it to operate numerous command interfaces. Its body strongly resembled the Praetorians deployed by the Collectors. The Collector General was a servant of the Reapers, specifically the one referred to as Harbinger, and was apparently directly controlled by Harbinger. The General could possess any normal Collector at any time, making them significantly more powerful and unlocking their biotic potential, making them a dangerous foe on the battlefield. This ability was taken advantage of by Harbinger while he possessed the General. The Collector General was always seen with glowing eyes, similar to what happened when he assumed control over an ordinary Collector. The only time they stop glowing is when Harbinger releases him of control a few seconds before he is killed along with the rest of the Collectors.

Mass Effect 2
After failing to acquire Shepard's body, the General attacked several human colonies in the Terminus systems, and began using the genetic material from survivors to create a Human-Reaper. This gained the attention of Cerberus and a resurrected Shepard, who the General sought to acquire alive if possible.

Final Hour
Commander Shepard and a team of specialists launched an assault on the Collector Base. The General rallied every available Collector drone to protect the base, and possessed multiple drones during the battle, but the tactics used by Shepard's fire team caused it to spread itself too thin. Shortly before the sabotaged base met its end, Harbinger, after berating the General for its failure and asserting the Reapers "will find another way", released its control over the Collector General, whose eyes lost their glow for the first time, suggesting that it was always under Harbinger's control. In the final seconds after being released, the Collector General appeared to be confused or dismayed at being abandoned, suggesting some level of intelligence and emotional capability remained. The General is then killed when Shepard activates a timed radiation pulse, killing all remaining Collectors on the base.