OVA
Description
Dark Mu is a cosmic entity and primary antagonist in *Mutant Turtles: Chōjin Densetsu Hen*, embodying chaos and destruction. She exists in direct opposition to her sister Kris Mu, the embodiment of harmony. Having existed for untold millennia, Dark Mu annihilated countless planets purely for amusement. Her ambitions escalated to destroying the entire galaxy, a plan only thwarted when Kris Mu sealed her within the purple MutaStone to prevent universal catastrophe; the stone was then hidden to prevent her escape.

Physically, she resembles a humanoid fairy: slender, with long black hair, green eyes, and distinctive moth-like antennae. Her attire consists of a red choker, red leather dress, red high-heeled shoes, red leather gloves, and bat-like wings. Possessing near-omnipotent power, her mere presence induces stellar collapse and eventual galactic destruction. She can trigger planetary-scale natural disasters like floods, earthquakes, and tornadoes. Dark Mu can also bestow immense power, exemplified by her transformation of Shredder into the massive, demonic Dark Devil Shredder. She emits an electrical aura capable of weakening adversaries, even entities of comparable power like Kris Mu.

Her narrative begins when Shredder, Bebop, and Rocksteady harness the Dark MutaStone's power, inadvertently freeing her. Upon release, her chaotic energy ignites worldwide cataclysms. She first attempts to obliterate Earth by empowering Shredder as her proxy. After the Turtles defeat Dark Devil Shredder, she retreats to space to personally initiate galactic annihilation. The Turtles counter by fusing into the composite entity Turtle Saint and executing the "Mega Final Saint Break" technique. This, combined with Kris Mu's sacrificial intervention, reseals both sisters within the MutaStone, which is then condemned to eternal exile in space.

Personality-wise, Dark Mu is sadistic, ruthless, and chaotic. She revels in destruction and shows no remorse for genocide. Her relationship with Kris Mu is devoid of affection; she willingly attempts to kill her sister to eliminate interference. While her nature as chaos incarnate influences her actions, she consciously delights in devastation and dismisses the concept of harmony as nonsensical.