Source: Empire of Bones, pg(s). 55
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A baykok is a flight-capable undead creature despite its lack of wings.
Those hunters who become utterly obsessed with the chase and indulge excessively in the savagery of the kill sometimes rise from death as baykoks. A baykok is devoted to the hunt and always seeks to prove its mastery of the hunt. It can devour its victim's soul in an attempt to make sure that the prey never comes back to seek revenge.