Known for his brilliant military strategies and his ability to cunningly exploit any situation for his own personal gain, Darth Decimus ascended to the Dark Council after the unexpected death of Darth Azamin at the hands of a Jedi strike team toward the end of the last war.
Many suspect Decimus aided the strike team on their mission in order to remove a powerful rival, but these suspicions were never proven. The Jedi all perished when the ship they used to escape Azamin's stronghold exploded due to a mechanical malfunction that was most likely due to sabotage.
Despite his wanton ambition, Decimus is fiercely loyal to the Emperor, and he was chosen to lead the Imperial invasion of Corellia. Living up to his reputation, Decimus devised a plan that allowed the Empire to seize control of the world with virtually no significant resistance, giving the Imperials an early upper hand over the Republic.