Blood of Hercules (Villains of Lore Series, Book 1)

Step into the Coliseum at the Spartan War Academy where monsters are made, immortality is won, and even a god can die...
Alexis Hert isn’t a hero, and she certainly isn’t a god. All she’s ever been is a survivor.
But the Fates disagree.
When a blood test leads to her admittance at the Spartan War Academy, she’ll have to do more than merely survive.
Alexis will have to claim her birthright: immortality.
But immortality is a privilege, one earned in the crucible of the academy, where the heroes are villains and classrooms battlegrounds. While gladiators Achilles and Patro, her demanding mentors, hone her into a warrior, Augustus and Kharon, her professors and the brooding heirs to the underworld, haunt her steps and her thoughts.
Because where there are gods, there are bound to be monsters, and there is more than one hunting Alexis...