Paratwa (3 Book Series)

From Book 1:Two hundred years after a nuclear apocalypse forced humanity to flee earth, humans still remember the most feared warriors of that planet—-the Paratwa, genetically modified killers who occupy two bodies controlled by one vicious mind. The legendary Paratwa named Reemul, known as the Liege-Killer, was the strongest of them all. Now someone has revived Reemul from stasis and sent him to terrorize the peaceful orbital colonies of Earth. Is this an isolated incident, or has the one who unleashed this terrible power announced a gambit for control over the entire human race?