The Human Equation — Kenneth Tam

The first novel in the Equations series: The human race was driven from the Earth in the mid-twenty first century, by an intelligent bio-weapon called Omega. Seven hundred years later, humanity's descendants return to Earth on a Quest fueled by a false religion, determined to reclaim their home. But since humanity's departure, Earth has come under the protection of a new race: wolves, cats and bears that were mutated into humanoid form by the bio-weapon before it vanished. These Earthers are better than humans in every conceivable way; they are too good to be true. And having learned from the wreckage of humanity's past, they are wary of humanity's return. Led by First Lord Setter Caine, these wise and idealistic beings must protect their home against human fanaticism...