The Rachni

The Rachni are an intelligent sentient race of insects. However, they are often very aggressive as whole, which has caused them to get into conflicts with other races. This aggressiveness is what also led to their extinction in the Rachni Wars. Although they may be extremely territorial, they try to stay away from other races and live on worlds other races can't live on, since their physiology can match that of even the strongest Krogan.

The Rachni are one of the most unique races in the Mass Effect Galaxy because of how they perceive the world and communicate. Overall, the Rachni perceive the world as a collective and are able to communicate with each other regardless of the distance. This psychic link allows them to experience the world as a whole through every other living Rachni, but this link can be interrupted by outside forces. This link can also lead to the Rachni as a whole to become closed off towards certain perspectives or to become manipulated by other people into a specific thought process. Although the Rachni have eyes, they see the world around them in auras and colors. Much like how we would see the world around us with heat vision, but,naturally, more detailed.

Lastly, the Rachni collective mind is managed by a Rachni Queen (or multiple Queens). In a way this is their form of government as the Queen(s) collaborative, filter, debate, manage, and control the Rachni brood's actions and thoughts. However, this is only because the Queen(s) have the strongest influence on the psychic link, but the Queen(s) can be manipulated or overridden by other forces.