The evil spirits who Mumm-Ra serves. They seem to be four entities who speak in unison indicating constant telepathic communication.
Unknown, though they are worshiped by and give power to Mumm-Ra. They were also worshiped by the Tiger Clan of Thunderians even after Mumm-Ra's fall, but when the Tiger King Javan refused to sacrifice his son Tygra as an offering to them, they released a plague that killed all the Tigers, but kept them in an undead form where by day they were tigers and by night they were monsters. Tygra and Lion-O managed to break the curse and allow the tigers to move on to the afterlife.
The spirits did not have it in their power to kill Tygra himself for unknown reasons, but stated that he would oppose them in the future as their reason for wanting him dead, foreshadowing his role in the Thundercats, and possibly indicating they fear the Thundercats as a unit.
The shapes of the spirits represent a Jackal, a Lizard, a Monkey, and a Vulture, much like the species of the henchmen of Mumm-Ra.