For every good there is an evil. Creatures born of seduction, rape, strange lusts, and fear, half-fiends represent the lasting aftereffects of evil in the world. Most have family ties to devils and demons, but half-fiends can spring from the entire spectrum of evil—from asuras to kytons to divs to oni and beyond.
Some sages insist that the minotaurs were once a noble people despite their barbarity, before being turned to demon worship. If so, the evangelists were probably half-fiends like Grazzajag, a traveling prophet of slaughter and rage who whips minotaur tribes into a fervor in the Maze Lord’s service and slays any chiefs who resist.
A lurking rooftop terror, Shadefang is a stealthy and malicious half-fiend wyvern unafraid to haunt the cities of men. Rather than smiting good, Shadefang’s daemonic bite is imbued with bane and ghost touch abilities that allow him to snap up the psychopomps that guide goodly souls to their rest.
A lammasu’s noble nature is intrinsically tied with its magical abilities. Thus the half-fiend Othenio, product of his mother’s violation by a pairaka, exists in a permanent state of magical backlash. As a result, he suffers a split personality—one minute the kind healer, the next a cause wounds-hurling calamity. What triggers his shifts is unknown; possible causes involve the sight of dwarven women, the sound of kwela rhythms, the smell of grass fires, and the presence of any paladin.
—Pathfinder Bestiary 171
While writing this post I discovered the time-sucking rabbit hole of delight that is a good baby name generator. “Othenio” means “give birth by night”!