Twilight of the Serpent

Bantam paperback, 1977. The Druid Cult was doomed to total annihilation by the invading Romans. But the mystical tribe of warrior-priests called up every weapon of man or magic to aid their sacred quest. Bold swords, brutal lusts and demon rites were all unleashed in a war that shook the walls of the universe. And ushered in the bloody dawn of man's awesome destiny.