Darkspore

The Crogenitors were a race of scientists that established a massive empire encompassing an entire galaxy. Many of them performed secret experiments on the populations they oversaw. Being masters of genetic manipulation, they used their knowledge to create a personal army of genetic heroes, called Living Weapons. However, the discovery of an experimental amino acid that bonds to DNA changes everything. Capable of achieving a millennium in terms of evolution in a matter of hours, it has an immense potential to manipulate life to levels never achieved before.
Unfortunately, E-DNA proves to be unstable. All of the test subjects who came in contact with it were transformed into uncontrollable genetic mutants soon named The Darkspore. Fearing these new creatures, the Crogenitors throw hero Xylan into exile for his behavior and negligence, outlawing the use of E-DNA. Xylan fakes his death. Believing himself able to control the power of E-DNA, he injects it himself. This act transforms him into the Corruptor — a mentally unstable, extraordinarily powerful mutant who can master all Darkspores. Determined to get revenge on the other Crogenitors and conquer everything, he gathers allies and strengthens the E-DNA mutagenic power. Afterwards, the Corruptor begins conquering planets of the Crogenitor empire, infecting them through the use of E-DNA bombs, and destroying Crogenitor fortresses with his mutants and war machines.
As the game begins, the player takes on the role of one of the last Crogenitors. Starting with only a few heroes, the player's goal is to purge the Darkspore from the galaxy, planet by planet, moving ever closer to the ultimate goal of destroying the Corruptor forces.