The Vorcha are a race of extremely adaptable but highly primitive creatures. They originate from a highly overcrowded world, and their fast breeding and aggressive mentality has led to constant warfare over diminishing resources. As a result of this conflict and the harsh environment, Vorcha have developed a close-knit clan based society, one that is constantly at odds with rival clans over the control of basic resources.
They are largely seen as a pestilence in the galaxy, as most species regard them as little more than savages and scavengers. They're not very intelligent, and are hostile to other species. The Blood Pack mercenary group often utilizes Vorcha as expendable infantry due to their savage nature and their ability to thrive in harsh environments.
The Vorcha have the shortest known lifespan of all the sapient beings in the Mass Effect universe, with an average life expectancy of twenty years. Their biology is also the most unique among sapient beings in the Mass Effect universe, allowing them to be very adaptable creatures. If a Vorcha is placed in an environment with high gravity, they will grow stronger leg and heart muscles. Or, if a Vorcha is badly burned or cut, it will grow thicker skin.
This unique biology allows Vorcha to adapt to almost any environment, and they can actually thrive in places that other beings would have difficulty functioning in.
However, a draw back to this, is that the Vorcha as a species can no longer evolve. Genetically, there is no need for widespread change, when Vorcha can adapt to any situation on an individual basis. Vorcha biology has remained pretty much unchanged for millions of years.
Their society is almost entirely dedicated to combat. In fact, combat is actually seen as a common form of communication among their species. Their society is a communal clan based one, as they prefer to remain near members of their own species, and do not fare well on their own or with other species. When a clan's numbers grow too large, the younger members will splinter off to form their own clans.
The Vorcha themselves are not a space faring race, and commonly escape their home world by stowing away on ships that have visited their world. Their adaptable nature allows them to escape into areas of the galaxy often seen as uninhabitable, and there they can breed and thrive. In populated areas though, they tend to stick to dark and grimy areas.
The Blood Pack often likes to sweep up groups of Vorcha, and put them through a great ordeal to turn them into effective and expendable soldiers. They are useful in this regard, as they can survive harsh conditions, and can heal quickly when they are wounded.
Some Vorcha have aligned their selves with the Collectors, with the promise of power and a better quality of life.