Vorcha

Known for their unique biology and aggressive behavior, the vorcha are a primitive race that live among the galaxy's darker and more dangerous locations, such as Omega. Many vorcha are trained by the krogan as mercenaries due to their savage nature and adaptability to different environments. The rest of galactic civilization regards them as pests and scavengers, and their presence is generally seen as a blight.

Overview
The vorcha originate from a small and overcrowded planet which has been largely stripped of natural resources by successive generations of this fast-breeding, savage species. The lack of resources has resulted in a tight-knit clan based society in which rival clans wage constant war against one another for control of scarce resources. Even as their population grows, the vorcha constantly fight each other in fierce competition over basic necessities. This constant warfare has had the twin effects of making each generation of vorcha stronger and more aggressive than its predecessor. However, their continual lack of resources have kept vorcha society extremely primitive.

Biology
The vorcha are the most short-lived sapient species currently known, with an average lifespan of only 20 years. The vorcha are known for a rather unique biology that differentiates them from other known species and which carries with it a striking set of advantages and disadvantages. The vorcha have clusters of non-differentiated cells, similar to those found on the Planarian worm of Earth. These cells allow the vorcha limited regenerative abilities, as well as the ability to adapt quickly to its environment, such as developing thicker skin after being burned or increased musculature to survive in high gravity. When a vorcha is injured or in distress, these cells move to the affected area and rapidly (~1 week) mature to specialized forms that will alleviate the issue.

A vorcha that is cut or burned will adapt to have thicker skin. The lungs of a vorcha placed in a barely-breathable atmosphere will adapt to better use the gases there. A vorcha subjected to high gravity will quickly develop stronger heart and leg muscles. Non-differentiated vorcha cell clusters do replenish themselves, but the process is slow. Generally vorcha can only adapt to a single environment within their brief lives. However, what cells are replaced allow them to heal rapidly, and even regrow lost limbs over a period of months.

However, as a consequence of this, the vorcha as a species no longer evolve as other races do. The vorcha equivalent of DNA has remained unchanged for millions of years. There is no need for them to evolve as a species when they can adapt as individuals.

Some vorcha have allied themselves with the Collectors, in an attempt to raise their quality of life.

Society
Vorcha society is built around combat. In fact, the vorcha use combat, both singly and in groups, as their default form of communication. The vorcha are a clan based people who prefer living in communal environments with others of their species to living alone or in the company of alien races. When a clan population grows too large, younger members will depart to start a new clan elsewhere. The vorcha are extremely aggressive, both against rivals of their own species and against any alien who stands in their way. Vorcha who have managed to escape their homeworld have a tendency to occupy uninhabited areas of space stations or larger spaceships.

The vorcha are not themselves a space-faring race, although many have found their way off-world as stowaways on ships visiting their homeworld. The vorcha who escaped their hostile homeworld did so by hiding on the ships of space faring races that had the misfortune of visiting their planet. Their adaptability and resilience allows them to flourish in the dark and dirty corners of the places they end up.

Seeing the potential of the vorcha's individual adaptability, krogan Blood Pack mercenaries often sweep pockets of vorcha, gathering them up and literally beating them into soldiers. Vorcha “trained” by this ordeal are stronger, faster, smarter, and more resilient than other members of the race. Gaining even a few vorcha gives a mercenary band a formidable advantage; each additional vorcha magnifies the gang’s combat ferocity exponentially.

Trivia

 * In the Star Trek universe, the Vor'cha class cruiser is a powerful warship used by the Klingon Empire.
 * The vorcha have some similarities to another Star Trek race, the Jem'Hadar, who are also warrior-based reptilians with a 20 year lifespan.
 * According to an article in Game Informer much of the vorcha's history, including how they developed their FTL was cut from the final game after Casey Hudson decided it didn't fit the vorcha's appearance and culture.