D-wolves are genetically engineered hunters and guardians of Leto II's Sareer. A pack of D-wolves chased Siona Atreides through the Forbidden Forest and killed the remainder of her rebel search party during a heist of two volumes of Leto II's personal journals.
The D-wolves have grey bodies and are "almost man-height at the shoulders". They are conditioned to stop pursuing intruders at the water edge of the Idaho River. Siona notes that the wolves are known for their keen eyesight, "Gaze Hounds in the ancestry of Leto's forest guardians". They are allowed to eat anything they hunted in the Forbidden Forest.