Saeki Karin
An Akelon who impersonated the deceased physicist Karin Saeki (佐伯 カリン Saeki Karin, episodes 1-12) upon 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 Gou arrives in time to fight her off. While overseeing Remls attacking his team-mates, Karin fights Tarius 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 Tarius, knocking her off the building to her death.
Karin (in her giant form)
However, she came to life before her body could be autopsied by the national defense group. Making her way to Ryujin Mountain, Karin summoned her UFO to heal her injuries before going after Tauron 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 Dolcruz are summoned to fight her. Though she had the upper hand against the two Chouseishin, Karin retreats to the valley hill to 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.