Dark One (The Dawn of Monster Kid)

The Dark One is a kaiju created by Toho and appears as the overarching antagonist of The Dawn of Monster Kid, first appearing as the main antagonist of the seventh and final season. It is an ancient cosmic entity that travels across the universe, destroying entire planets and galaxies.

Appearance
The Dark One is a large enormous alien entity, usually resembling a swirling vortex of black, gray and blue clouds. In its true form, the Dark One resembles a giant dragon-like creature.

Personality
The Dark One is a malevolent being that desires to consume and destroyed entire worlds. It's reputation is known to the Blight, Drox and the Ancient Ones as they all fear the entity's power.

Biography
The Dark One is an ancient cosmic abomination, a hyper evolved extraterrestrial organism who's existence predates the universe itself. It's true name is unknown or where it came from, some legends believe that the Dark One is a living embodiment, born of negative emotions. For thousands of years, the Dark One has destroyed numerous stars and planets, leading the extinction of many civilizations. When it attacked to the Milky Way Galaxy, the Dark One arrived on Earth and was defeated as the Ancient Ones manage to imprisoned the entity in another dimension.

The Dawn of Monster Kid: Origins
In a flashback, Myriad reveals it was created to protect his creators' home planet from the Dark One.

Portal Creation
The Dark One can create portals to anywhere in the universe.

Shape-Shifting
The Dark One can shapeshift into any form it chooses.

True Form
The Dark One can transform into its original true form.

Planet Destruction
The Dark One can destroy an entire planets.

Trivia

 * The Dark One is similar to planet destroying beings like Galactus from Marvel Comics, Unicorn from the Transformers franchise and The End from the Sonic the Hedgehog franchise.