The virulent Terror Serum serves two purposes: keeping the recipient alive in the toxic In-Between, and with an additional infusion through the Applicator, tainting the victim's blood with the Benefactors corruption. The Serum has taken an age to perfect, with a macabre trail of victims in the wake of its first success: the Experiment. Deathless hosts of pure evil, the Terrors seek to drive the Innocent insane before executing them in service of their true masters.