Underland (Renquist Quartet)

Victor Renquist, centuries-old master of a small colony of Nosferatu, has been "recruited"-forcibly-by an undercover branch of the National Security Agency, Paranormal Operations and Research. They need his help. It seems that certain members of Hitler's Third Reich escaped to a secret world below Antarctica, taking with them some very advanced technology. Human teams have failed to infiltrate the base, and Renquist is the NSA's last chance.

The team is small: Renquist; his right-hand man, Lupo; an extremely unorthodox hardline NSA operative named Jack Coulson; and Thyme Bridewell, a failed NSA brain-control experiment originally intended as Renquist's lunch. What they find in Underland taxes even Renquist's supernormal powers. The quondam Nazis have some very powerful allies -- the Dhrakuh, a race of sentient reptiles from the dawn of time. Their goal is nothing less than the conquest of the entire world.

To make matters worse, Renquist is hampered by some throwbacks from his own race and by the unexpected arrival of one of his own colony members, Julia, together with Philipa, a darklost whom Julia has led through the Change into Nosferatu.
The future of civilization hangs in the balance.