The Hed'em'disol were a race of genetically engineered, telepathic Damiani, bred during the rule of Pad'gy D'ullh. The Hed'em'disol were used to employ the Chova, a telepathic weapon which spawned nightmares and waking hallucinations in its victims. The Hed'em'disol died out following the overthrow of Pad'gy. (TNG comic: Perchance to Dream: "By a Sleep to Say We End")