What is the climax of allies of the night?

In "Allies of the Night" by Darren Shan, the climax occurs when Darren, Mr. Crepsley, and Harkat fight against the vampaneze in the subterranean tunnels to prevent them from executing the plan to kill thousands of innocent humans. The battle is intense, with high stakes and emotional tension as the fate of the human world hangs in the balance. Ultimately, Darren must make a difficult decision that will have lasting consequences for his relationships and his role in the vampire world.