Liege Killer is the first book in a science fictiontrilogy written by American writer Christopher Hinz. The book and its sequels Ash Ock and The Paratwa are set in Human Colonies in orbit around a desolated post apocalyptic Earth.
The Paratwa the antagonists of the books are the result of experimentation on human embryos in the near future. The result of which produces a new species: the Paratwa, a single consciousness occupying telepathically linked bodies. The Paratwa are highly skilled warriors but look like normal people and are not necessarily identical twins, and can even be a pair of male and female. The only way to identify a Paratwa match is by inflicting a great deal of pain one of them, and observing the pain in the other.
The books follow the activities of humans and Paratwa as these old enemies are reunited more than a century after the earth's apocalypse during which humans had thought the Paratwa race had become extinct.