Isolus

 is a minor antagonist in the series.

Bio
A female ice-elemental monster who uses ice attacks, wields a sword and shield. In "The Spy," Isolus is sent to Earth and disguised herself as a foreign exchange student named Ilse in order to learn the true identity of the Galactic Sentinels. Reprogramming the power portal, Ilse ends up in the desert and transforms into Isolus. The Galactic Sentinels head to the desert and battle Isolus. She manages to freeze Gordon who is thawed by Swinton. The Galactic Sentinels form Knighttron who deflects Isolus' ice attack back at her. Emperor Gorganus plans to reconstruct her while using her residue for his drink. In "The Y Files," Emperor Gorganus sends Isolus to Earth's desert in order to start a new Ice Age. When Nimbar detects this, he sends the Sentinels. Isolus returns to Earth and fights the Galactic Sentinels where Isolus ends up freezing Apollo enough for the Sentinels to retreat back to Nimbar. In their next battle, Isolus makes their weapons disappear, the Sentinels form Knighttron and fight Nitghttron. After disarming Isolus, Knighttron ends up deflecting Isolus's ice attack back at her. With a new chip Gorganus added in her in "Take Two Galatical Sentinels and call Nimbar in the Morning," she was able to alter the Earth's climate. Gordon got sick and so did Nimbar and Drew. Taurus had to fight her to get a special bark to get Nimbar and everyone feeling better. When they were better, they defeat Isolus one last time.

Appearance
Isolus slightly resembles a human, wearing a blue suit but with a green alien face.