Create Chosen One

Only wizards of evil alignment may cast this spell, which consists of a series of magical rituals and torments intended to turn a normal human (of up to 3 HD) into a maddened, murderous creature known as a Chosen One. Victims must be bound and helpless in order for the spell to work. After its casting is completed, the victim must successfully save vs. death magic or be transformed into a chosen one under the control of its creator.
 

Through wretched rituals and torments over the casting time, you can attempt to convert a single Human of CR or Level 3 or less into a Chosen One. The target must make a Constitution Saving Throw, having its form twisted into a hideous caricature on a failure—the face contorts, teeth elongate, and the skin transforms into a tough, leathery protective sheathing. Its hands are gnarled and stretched, ending in wicked, filthy claws. The Chosen One is under your control, but is not completely reliable. Occasionally, their conditioning breaks down and memories of their past lives as well as the cause of their pain floods their minds. Each round while in combat, there is a cumulative chance that it breaks free and goes berserk. If this happens, the Chosen One screams horribly and immediately leaves combat, running away to find and slay its master, fighting only those who stand in its way.