TV-Series
Description
Klein stands as a high-ranking elite within the antagonistic organization Labyrinth, acting directly as Moebius's subordinate and messenger. He exhibits unwavering loyalty to Moebius and maintains a cold, emotionless demeanor, devoid of empathy, viewing failed members as disposable.

In human form, Klein possesses light skin and light blonde hair with a mature expression. His dark clothing features gold accents, a cape-like garment adorned with stylized ram-horn designs, a long fitted skirt-like piece, and black pants or leggings paired with visible off-white socks or cuffs, lending an academic or mystical air. His monstrous form transforms him into a large humanoid lizard: a muscular, black and gold armored torso, clawed hands, a grayish-brown fur-like ruff framing his head, red eyes, and a dark gray serpentine tail.

Artificially created by Moebius using lizard DNA (revealed in episode 49), Klein frequently relays Moebius's commands to agents like Eas, Westar, and Soular. He notably sends the communication confirming Eas's predetermined death. Her subsequent resurrection as Cure Passion provokes horror in him, a rare display of emotion.

His abilities include teleportation and expert navigation of Moebius's computer systems to monitor Labyrinth's inhabitants. In lizard form, he possesses significant strength and speed, enabling him to overpower the initial trio of Cures. Later, after witnessing Labyrinth's inhabitants support the Cures following Northa's defeat, he confronts them directly. He agrees to fuse with Northa, creating a powerful dragon-hybrid entity. This fusion withstands the Cures' strongest attacks—Triple Fresh and Happiness Hurricane—and breaks free from Lucky Clover Grand Finale. However, the combined entity is ultimately defeated by the enhanced power of the Cure Angels and their attack, Loving True Heart, reverting Klein and Northa to their original forms.

His name derives from the mathematical concept of the Klein bottle, an infinite object, complementing the theme of infinity associated with Moebius, named for the Möbius strip.