Runehounds are medium-sized aberrations with slick, pale, mottled skin often tattooed with garish patterns. These creatures can grow up to 6 feet long, 3.5 feet tall at the shoulder, and weigh up to 360 pounds. Instead of a head, a long serpentine neck extends from their back, ending in a grotesque maw filled with multiple rows of teeth. Though blind, they possess uncanny blindsight out to 500 feet due to their psychic senses.

Runehounds communicate with clicks and squeals and understand Undercommon. They use their psychic scent to track foes, gaining a significant bonus on Survival checks. In combat, they use their speed and vile spew attacks, which can either be a damaging acid stream or a sticky goo to entangle enemies. They favor flanking and staying out of melee range unless necessary, making use of their extended reach to strike from a distance