Mortal Gods: THE GODDESS WAR: BOOK TWO (The Goddess War, 2)

As ancient immortals are left reeling, a modern Athena and Hermes search the world for answers in Mortal Gods, the second Goddess War novel by Kendare Blake, acclaimed author of Anna Dressed in Blood.
Ares, god of war, is leading the other dying gods into battle. Which is just fine with Athena. She's ready to wage a war of her own, and she's never liked him anyway. If Athena is lucky, the winning gods will have their immortality restored. If not, at least she'll have killed the bloody lot of them, and she and Hermes can die in peace.

Cassandra Weaver is a weapon of fate. The girl who kills gods. But all she wants is for the god she loved and lost to return to life. If she can't have that, then the other gods will burn, starting with his murderer, Aphrodite.

The alliance between Cassandra and Athena is fragile. Cassandra suspects Athena lacks the will to truly kill her own family. And Athena fears that Cassandra's hate will get them all killed.

The war takes them across the globe, searching for lost gods, old enemies, and Achilles, the greatest warrior the world has ever seen. As the struggle escalates, Athena and Cassandra must find a way to work together. Because if they can't, fates far worse than death await.