Where many of Skeletor’s forces maybe monsters or sorcerers, Tri-Klops is instead a highly skilled hunter and swordsman. Viewed as a physical match for He-Man in strength and ability, Tri-Klops is aided by the visor atop his head offering three modes of vision. For Gammavision, the warrior can see through or around objects; Distavision allows the hunter to see far distances; and Nightvision allows Tri-Klops to see clearly in the dark. Despite his physical abilities, Skeletor generally relies on Tri-Klops’ ocular capabilities working as a spy and guide and is one of his most loyal soldiers (of which the sorcerer is in short supply). Among the Mutants, Mumm-Ra has no one that corresponds to Tri-Klops but one of his most present lackeys is Jackalman. The most cowardly of the Mutants, Jackalman was the leader of his species of Mutant and one of a handful of Mutant survivors to follow the ThunderCats to Third Earth. Therein, the Mutants bowed to the power of Mumm-Ra but hold no true allegiance to him. Jackalman wields a club in battle and often pilots a Skycutter for transportation.
Viewed as the right hand to Skeletor, Beast Man trained and maintained an army of beasts of all types save aquatic (leaving Mer-Man to fill that hole) often employed in his master’s plans. Generally loyal, Beast Man often plotted overthrowing Skeletor which could be attributed to the abuse his master heaped upon him (as time and again Beast Man was the receptacle for Skeletor’s frustration and rage). One of a small few of Skeletor’s forces with strength comparable to He-Man, Beast Man is often seen wielding a whip (heralding back to his role as a beast tamer). His strength, however, was often times negligible because He-Man could outwit the dull creature almost without fail. Mumm-Ra employed a Mutant with great strength but little guile in Monkian. Leader of the Simians and part of the Mutants that followed the ThunderCats to Third Earth, Monkian generally acted as a spy for Mumm-Ra and was oft to flee in battle when confrontations appeared too challenging. In battle, Monkian wielded a chained mace and a shield with his face which projected cannonballs from its mouth. Generally, he pilots a Skycutter.
An incompetent cyborg in the employ of Skeletor, Trap Jaw nonetheless is a talented inventor that happens to have very little sense. Part of Skeletor’s elite circle of followers, Trap Jaw often fought alongside Beast Man in battle. Trap Jaw has a mechanical jaw seemingly able to chew through anything and is apparently able to eat most things (even the mineral Eternium which briefly somehow made him a physical match for He-Man). His most notable feature is his robotic right arm which is interchangeable for a number of tools including an energy rifle, clamp, hook, battering ram, and more. Arguably the closest Mutant to Trap Jaw in Mumm-Ra’s employ is Slithe. Leader of the Reptilian Mutants and de facto leader of the Third Earth Mutants in general, Slithe lead the Mutant band that followed the ThunderCats to Third Earth where his species appears to have the greatest numbers to have survived the journey and remained on the planet (evidenced by Reptilians often seen guarding and servicing Castle Plun-Darr, the Mutants’ base on the planet). Undoubtedly the sliest of the Mutants, Slithe often allows his impatience to ruin his plans leading him to take out his frustration on his subordinates. In combat, Slithe wields a poleaxe and warp gas grenades which instill fear in those that breath it. Slithe generally pilots the Nosediver.
Skeletor’s apprentice and the most likely to betray him (drawing parallels to Hordak and Skeletor), Evil-Lyn is the sole female in his inner circle and undoubtedly his most intelligent ally. A master of illusion magic, Evil-Lyn is at ease being Skeletor’s second-in-command and often times will go out on her own in the pursuit for more power. While Evil-Lyn is a sorcerer and Teela a warrior, the pair often happen upon each other be it in the battlefield or during one of Evil-Lyn’s personal journeys for magic. Evil-Lyn wields a magical scepter affixed with a crystal ball atop it. Among Mumm-Ra’s Mutant forces, none are more capable than that of Ratar-O. A general in the Mutant legions, Ratar-O was requested by Vultureman to assist with the ThunderCats. Wielding the Rats’ Eye, a pair of daggers infused with mystical energy, Ratar-O pairs his brilliant strategic mind with his deadly tools to be one of the ThunderCats’ most dangerous foes. The Rats’ Eye have a myriad of abilities such as producing powerful blasts of force, levitating objects, and enabling flight (which Ratar-O pairs with boosters in his foot apparel for enhanced speed). It would in fact be Ratar-O’s ancestor Ratilla who wielded the Sword of Plun-Darr which inevitably destroyed Thundera. Ratar-O’s spaceship is the Ratstar.
When Keldor was born to the Eternian royal family, his blue skin was an indication within him resided the blood of the reviled race known as the Gar. Ultimately banished, Keldor’s younger brother Randor would later inherit the thrown. In his journeys, Keldor encountered the spirit of Hordak, chief disciple of the powerful Horde Prime. Keldor became Hordak’s apprentice, taking the name Skeletor. The pair plotted to kidnap the children of Randor and his bride Marlena as Hordak learned they were destined to wield great power. The plan was only partly successful as Hordak managed to abscond with Princess Adora as Skeletor betrayed him and abandoned him in another dimension in order to leave Eternia for himself alone. However, when it appeared Skeletor had finally garnered enough power and forces to take over Eternia, Prince Adam was given the Sword of Power and, as He-Man, vanquished the villain (as Skeletor then sought to make the Power of Grayskull his own). While the likes of Hordak and King Hiss would arise to challenge Eternia, the conflict between He-Man and Skeletor appears to be ever ongoing. Undoubtedly, Skeletor’s parallel within ThunderCats is that of Mumm-Ra the Ever-Living.
Unwilling to give in to death, Mumm-Ra gave himself over to the Ancient Spirits of Evil, four deities of immense power. In exchange for eternal life, Mumm-Ra became the slave of the Spirits, ruling over Third Earth in their stead. Thousands of years later, the ThunderCats would come to Third Earth to escape the destruction of their homeworld. Within their possession was the Eye of Thundera, an artifact of such power, Mumm-Ra could use it to not only be free of the Spirits, but even more powerful than before. However, Mumm-Ra’s attempts to secure the treasure failed. As the Mutants arrived on Third Earth, Mumm-Ra sought to enslave them to his cause but they too failed to defeat their mutual enemy. Ultimately, the Ancient Spirits of Evil banished Mumm-Ra for failing to destroy the ThunderCats who essentially usurped their rule of Third Earth. When the ThunderCats sought to rebuild New Thundera (which Mumm-Ra resurrected from the destruction of Thundera and constructed a Black Pyramid upon it for the Spirits), Mumm-Ra was brought back to continue his efforts with increased aid from his masters. Mumm-Ra would secure the Sword of Plun-Darr, the only weapon in the universe almost comparable in power to the Sword of Omens. While new threats like the Lunataks and the Berserkers would emerge, Mumm-Ra remained the ThunderCats’ greatest foe.
Honorable mentions: Vultureman, Driller, Ma-Mutt, Mer-Man, Faker, and Panthor.