Akelon
The Akelon race were the first alien menace to battle the Gransazers, their abilities include stretching arms, super speed, and shooting blasts of lightning. But their greatest strength is the Crystal Lens, a technology that can either heal or revive an Akelon or turn it into a Akelon Nova-Beast.
Karin
An Akelon who impersonated the deceased physicist Karin Saekiupon. Her arrival on Earth two decades ago to survive within Earth's atmosphere. Acting as a guide to the Wind Tribe, she convinced them that the other Sazers were a threat to the planet and must be destroyed. Subtly, she built a relationship with Akira that ensured his loyalty to even further tie him to her. Once Ryouko and Jin leave her, Karin reveals her true Akelon identity to kill them until Tenma, Mika, and Go arrive in time to fight her off. While overseeing Remls attacking his teammates, Karin fights Tarious until the Wind Tribe notice the explosion of their fight with Akira seeing Karin for as she really is, revealing she fell in love with the human and offered to spare his life. But in spite of his own love for her, Remls is forced to kill her to save Tarious, knocking her off the building to her death.

However, she came to life before her body could be autopsied by the national defense group. Making her way to Ryujin Mountain, Karin summon her ship to heal her injuries before going after Tawlon and severely wounding him to call out the Gransazers. After being manhandled by the Fire Tribe, Karin assumes her Nova-Beast form and destroys the city as Garuda and Dolcross are summoned to fight her. Though she had the upper hand against the two Chouseishin, Karin retreats to the valley hill heal her burn injuries by Garuda, taking Akira into the beast for one last chance to join her before she resumes her attack. After Remls breaks free from her body, the assembled Gransazers managed to destroy Karin's UFO before she herself is destroyed by the three Chouseishin in Episode 12.

Clo-Akelon
From the remains of Karin, Tsubaki of the JSDF science division begins to secretly mass-produce stronger Clo-Akelon that would serve as bio-weapons to ensure Japan would be a greater world power. Test Subject One was sent after Shiroi Kuga to reclaim the Crystal Lens when confronted by Tarious and was later destroyed. But once the Crystal Lens is back in Tsubaki's grasp, Test Subject Two turns on his creators upon being exposed to the Crystal Lens, stealing it while killing any soldier in his way of escape.

But once losing the Crystal Lens, the Fire Tribe arrive in time to drive the clone off with Tsubaki's platoon in pursuit. However, the Akelon Clone manages to reclaim the Crystal Lens and transforms into Clo-Akelon Nova-Beast form. The monster was slowed down by Youhei as it destroy the monster's crystal lens as the Chouseishin arrive and Daisazer finishes the clone off. Appeared in Episodes 27-28.

Ruby
Though an agent of Warp Monarch, Ruby intended to stop Belzeus' scheme by heading to Earth to find Ran. Though thought as an enemy because of Karin's actions, Ruby reveals she's on the Gransazers' side when she saves Ran. Wounded while protecting Ran from Algol, Ruby is taken the JSDF. Once healed, she help Ran awaken as the Communicator to become the vessel of communication between Earth and the Warp Monarch high council. Appears in Episodes 46-51.