|Voiced by Henry Corden|
|Powers and Abilities:||Spellcraft; Beam-eyes|
|Fate:||covered in stone|
Gemini (aka Janus) is an evil cyborg sorcerer, with a split-personality and two faces on the same head: one who is aggressive and short-tempered; the other calm and diplomatic, but no less evil. To switch from one face to another, his helmet closes over the current face, and his neck rotates (180 °), revealing the other face.
In Last Train to Doomsday, Thundarr encountered Janus and after Gemini was revealed to be alive, Thundarr knocked him into the magic pool where his rock soldiers incubated their young. Gemini was apparently turned to stone. But it's hard to say if a wizard is ever truly dead.
- Teleportation capable of moving himself and half a dozen of his robotic knights at once.
- A Barrier of blue flame.
- Laser-like energy beams from his eyes
- A red beam that can immobilize people.
- He also created clouds to use as personal transport, and animated the Statue of Liberty to fight Thundarr.
Gemini equipped the Groundlings with motorcycles and beam-clubs and gave them a magic well to communicate with him. Gemini used his magic well to watch nearby events unfolding. He was also able to make the water in the well he gave to the Groundlings move. He also created robotic knights and equipped them with a helicopter and metallic beam weapons similar to the beam-clubs. the helicopter appeared to have an auto-stabilizer. Gemini's citadel had laser-like beam defenses. He kept Ariel caged; inside of which, she could not use her magic.