JAMES HERBERT the rats trilogy

The Rats:
It was only when the bones of the first devoured victims were discovered that the true nature and power of these swarming black creatures with their razor sharp teeth and the taste for human blood began to be realised by a panic-stricken city.

Lair:
The mutant white rat had grown and mated, creating offspring in its own image. They dominated the others, the dark-furred ones, who foraged for food and brought it back to the lair.

Domain:
The long-dreaded nuclear conflict. The city torn apart, shattered, its people destroyed or mutilated beyond hope. For just a few, survival is possible only beneath the wrecked streets - if there is time to avoid the slow-descending poisonous ashes.