Book: Fallen Leadership.
Kovik's twisted science is believed to be responsible for the Devil Splicers' SIVA-fueled evolution. But his ambitions didn’t stop with the augmentation of Fallen from ether-starved pirates to half-machine demigods. Instead, the mad Priest’s research took a far more sinister turn as he sought to control and weaponize the more aggressive aspects of the Hive’s mysterious biology.
If Kovik’s experiments were allowed to succeed, or be furthered in his absence, there is no telling how dangerous the Devil Splicers could become