Future Earth

Very little is known about Blackstar's Earth, though its technology is undoubtedly far advanced, as evidenced by Blackstar's "photon-based" ship and Katana's "fusion-drive" timeship capable of multidimensional travel. Neither Blackstar nor Katana bear any insignia related to any agencies in the real world. Blackstar's insignia appears on his golden collar.

Planet Sagar

Sagar, where John Blackstar ends up being stranded, is located in an ancient alien universe. It is subject to attacks by the evil Overlord, who seeks to conquer the planet.

John Blackstar

John Blackstar's race is not specified in the series, though it is often speculated that he could have Native American heritage and ancestry, anticipating Bravestarr, a later Filmation series, by roughly six years.

As an astronaut, Blackstar might have been extensively trained in many fields. He is intelligent, and he often prefers to outsmart his opponent rather than rely on physical talent, even though his constant contact with the Starsword grants him super-human athletic abilities and near invulnerability.

The Powerstar's two halves

The Powerstar was a mighty magical weapon that was split in two through unknown events, with Blackstar and the Overlord each possessing one half. Blackstar's weapon, the Starsword, is able to absorb, store, and reflect any external form of energy, and is virtually indestructible. It can also produce blasts of pure energy capable of destroying a target. The weapon generates an invisible "aura" that imbues Blackstar with superhuman senses, strength, endurance, reflexes, speed, agility, and almost unlimited invulnerability to harm and extreme temperatures. Presumably, the Overlord's Powersword confers similar abilities. For a brief time in the episode Spacewrecked, the Starsword and the Powersword are re-joined together into the Powerstar.

Blackstar's fate

In the sixth episode, "Spacewrecked", Blackstar was briefly reached by his former Earth girlfriend, Lieutenant Katana, who spent some time on Sagar before a misadventure with the Overlord forced her to leave. Katana did not appear in any other episodes, although the story ended with her asking a superior for permission to organize an armed rescue mission.

Main

• John Blackstar (voiced by George DiCenzo) – The main protagonist of the series. John Blackstar is an astronaut who ends up stranded on the planet Sagar where he takes part in the battles against Overlord.
• Warlock – A winged, green equine-like dragon mount ridden by Blackstar, which he called a "dragon-horse". He is highly intelligent and agile in flight, and is able to breathe fire like all dragons.
• Klone (voiced by Patrick Pinney) – A tall, pale green elf-like shapeshifter with long white hair and a ready wit who assists Blackstar against the Overlord.
• Mara (voiced by Linda Gary) – A purple-skinned enchantress who is Blackstar's ally. She is capable of telekinesis, telepathy, levitation, forcefield projection, illusions, magic blasts, and teleportation. In "City of the Ancient Ones", it is revealed that she is at least a few centuries old.
• Trobbits – A portmanteau of troll and hobbit, they are the inhabitants of the Sagar Tree. The pink-skinned, white-haired little Trobbits rescue Blackstar upon his arrival on Sagar. They are likely inspired by the Seven Dwarfs. Some of the known Trobbits are:
  • Balkar (voiced by Patrick Pinney) – The King of the Trobbits and the mentor of John Blackstar. He controls elemental magic and is also a great alchemist.
  • Rif (voiced by Frank Welker) – The Trobbits' grumpy, flame-capped cook.
  • Terra (voiced by Patrick Pinney) – The gardener who talks to plants.
  • Burble (voiced by Frank Welker) – The babbler who swims very well and freezes during the winter.
  • Carpo (voiced by Alan Oppenheimer) – The carpenter who gnaws wood with his beaver-like teeth to construct things.
  • Poulo – The mute whistler, youngest of the Trobbits.
  • Gossamear (voiced by Frank Welker) – The huge-eared flying one who is the scout and lookout.

Villains

• Overlord (voiced by Alan Oppenheimer) – The primary antagonist of the series. The large, muscular purple-skinned tyrant plots to rule all of the planet Sagar and wields one half of the PowerStar called the Power Sword and constantly seeks the other half the Star Sword which John Blackstar now wields.
  • Vizier (voiced by Alan Oppenheimer) – Overlord's short, blue-skinned and purple-robed right-hand man and companion. He is an expert at mind-control and conjuring.
• Lava Locs – They appear in "Search for the Star Sword" and "Spacewrecked". The Lava Locs they are semi-intelligent creatures that can harden into volcanic stone and emerge from volcanic stone. They worship the Overlord and present him offerings at their temple.
• Alien Demons – They appear in two episodes. In "Spacewrecked", they appear as minions of the Overlord and Vizier. In "The Crown of the Sorceress", they are summoned by Taleena. The Alien Demons look a bit like evil gremlins and their toy figures came with each villain character.
• Palace Guards – Only appearing in "The Quest", they are the Overlord's beak-faced minions who guard the Ice Palace.
• Taleena (voiced by Linda Gary) – Only appearing in "Crown of the Sorceress", Taleena is a high priestess of the Demonlands and one of the minions of the Overlord. She was last seen consumed by the demonfire of her own making.
• Shaldemar (voiced by Alan Oppenheimer) – Only appearing in "The Zombie Master", Shaldemar is an ally of the Overlord and the ruler of Marakand. Shaldemar was last seen turning to smoke after a blast from the Star Sword shattered the Sphere of Souls, releasing the captured spirits.
• Isogul – Only appearing in "The Air Whales of Ancar", he is the king of the Vampire Men who blasts the Star Sword with evil magic, making it unstable. The evil can only be purged by the song of the Air Whales of Ancar.
• Nihilis (voiced by Alan Oppenheimer) – Only appearing in "The Air Whales of Ancar", Nihilis is the captain of a flying whaling ship when he tries to capture the Air Whales and turn them into servants of the Overlord. His daughter Lyla is trying to get him to see the error of his ways.
• Kadray (voiced by Alan Oppenheimer) – Only appearing in "Lord of Time", Kadray is a time lord who rides a flying bull named Triton. He uses a time scepter to control time. His powers in the end backfire and is turned into a baby. Kadray was last seen in the care of the desert sprites.
• Neptul (voiced by Alan Oppenheimer) – Only appearing in "Kingdom of Neptul", Neptul is the ruler of Aquaria and a servant of the Overlord. He attempted to steal the Star Sword from Blackstar.
• Typhot (voiced by Alan Oppenheimer) – Only appearing in "The Mermaid of Serpent Sea", Typhot is the captain of a group of undead pirates and enemies of the Mermanites. He is an ancestor of the Overlord. Typhot was last seen as a flying manta ray flying to Overlord's icy castle.
  • Sirk – Only appearing in "The Mermaid of the Serpent Sea", Sirk is Typhot's first mate.
• Breelorand – Only appearing in "Overlord's Big Spell", it is a giant magic-consuming demon that Overlord foolishly summoned to destroy the rebellion that went out of control. Breelorand's rampage forced the Overlord to team up with Blackstar to defeat it as it began destroying the planet Sagar.
• Crios (voiced by Alan Oppenheimer) – Only appearing in "Lightning City in the Clouds", Crios is an Ice King whom the Overlord sends to capture Lelanna and use the special key she has to open the Box of Seasons and obtain the Weatherseed for the Overlord's purpose. In exchange, Overlord would have him rule winter on Overlord's behalf. When the key was destroyed and the Box of Seasons opened, Crios vanished in the dawning spring.

Supporting and minor

• Amber (voiced by Linda Gary) – Only appearing in "City of the Ancient Ones", Amber is a sorceress who is hundreds of years old and is worshiped by the Cave Apes. With the help of Vizier, the Overlord awakens her from her crystallized sleep and forces her to lead him to Tamboriyon. At the Overlord's command, Amber imprisons Klone and the Trobbits. She is redeemed by Blackstar and Mara. While Amber herself is human, she has a gnarled monstrous hand for reasons that were left unexplained.
• Storm (voiced by Linda Gary) – Only appearing in "The Lord of Time", she is Queen of the Amazons and ally of Blackstar.
• Tholen – Only appearing in "The Lord of Time", he is king of the Desert Sprites, a race of pacifists who guard the Fountain of Fire from evil.
• Queen Brindell – Only appearing in "The Mermaid of Serpent Sea", she is the Queen of the Mermanites and ally of the Trobbits.
• Puffin – Only appearing in "The Mermaid of the Serpent Sea", she is an extremely chatty Mermanite child who befriends Poulo.
• Tyson – Only appearing in "The Quest", he is the Elder of the Desert Dwellers who guard the Healing Stone.
• Emerald Knight – Only appearing in "The Quest", she started out as a servant of the Overlord who gave her armor that restored her youth. Realizing the error of her ways, Emerald Knight decided to stay with the Desert Dwellers and help guard the Healing Stone.
• Leilanna (voiced by Linda Gary) – Only appearing in "Lightning City in the Clouds", she is keeper of the key to the Box of Seasons and possibly a demigoddess. Her opposite counterpart is King Crios.
• Flame People – Only appearing in "Kingdom of Neptul", they are fire elementals who help Blackstar & the Trobbits fight Neptul and his Amphimen.
• Delia – Only appearing in "Tree of Evil", she is a Wood Sprite (called a dryad), whose forest is tainted by evil when the Overlord creates an evil copy of the Sagar Tree as a trap for Blackstar and Klone.
• Lyla – Appearing in "The Air Whales of Ancar", she is the daughter of Nihilus who falls in love with Blackstar and helps him defeat her father. She vows to make her father change his ways.
• Grogon – Only appearing in "The Air Whales of Ancar", he is an Ape Man who speaks in the third person. Grogon helps Blackstar rebel against Nihilus.
• Warhoun – Only appearing in "The Air Whales of Ancar", he's an ancient and powerful Air Whale who befriends Gossamear.
• Thorg – Only appearing in "Crown of the Sorceress", he is the leader of a people imprisoned by the evil magic of Taleena. He becomes an ally of Blackstar.
• Prince Dal and Princess Loweena – Only appearing in "The Zombie Masters", they are the co-rulers of the city of Gondar. It is destroyed by Shaldemar, but Blackstar defeats him with Prince Dal's help. Dal and Loweena claim the floating city of Marakand as the new home for their people, becoming powerful allies to Blackstar and friends.

Toys

Galoob produced action figures from 1983 to 1985 after the show's cancellation, attempting to tap into the He-Man boom. The first series was re-released alongside the second and third series of figures with "laser light" stone-sparking action. Evil characters were packaged with demons while good characters were packaged with Trobbits. Trobbits were also packaged individually with Rif, Terra and Gossamer being the tougher ones to find.
Warlock the dragon and the Space Ship were each released in two color variations. Also released were Triton, Kadray's flying bull, the Trobbit Wind Machine and Battle Wagon. The Ice Castle was constructed with very thin plastic, making it very fragile.
In Greece, Blackstar action figures (the "laser lights" with stone-sparkling action version) were released under the name "Κυρίαρχοι του Σύμπαντος" (Masters of the Universe) by ElGreco toy company, until they were eventually phased-out by the introduction of He-Man and the Masters of the Universe.

Comics

Two independent comic adaptations were made for the French market. One was a 3-episode series by artist Christian Gatignol (a.k.a. "Gaty") published by Éditions Vaillant in their long-running comic magazine Pif Gadget.^[9] The other was a 46-page one-shot published by Éditions LUG (then the publishing house translating the bulk of Marvel Comics in French) by artist Jean-Yves Mitton, the creator of famed French super-hero Mikros. While Gatignol's version stays close to the original, Mitton went his own way with the Blackstar mythos, creating new enemies for Blackstar to fight (Antrax the coal giant, Telekrane the phantom witch), and stating that Blackstar and Mara had a romantic relationship. While Katana does not appear, she has a counterpart in Blackstar's original girl-friend from Earth, Leia, who appears in a flashback. It is also explained that Blackstar suffers partial amnesia from his crash on Sagar and had all but forgotten Leia when he started his relationship with Mara.^[10]