Imugi

Overview
A creature stationed at one of the Devil's prototype dungeons.

Appearance
It looks like a giant snake, with scales formed by the condensation of miasma. It has shiny yellow eyes, and big teeth line the inside of its body.

Abilities
It has the ability to purify chaotic miasma into pure miasma.

History
An earthworm that fell to the Demon Realm from another world. Though it should have died in that environment, it miraculously mutated into a creature that gained miasma by ingesting the soil there, somehow adapting. At first, it was just barely able to accept some of the miasma, and threw up what was left of it. However, by continuing to do the same thing repeatedly, it was able to calmly embrace and savor the soil of the Demon Realm. Through trial and error, its body transformed with miasma and succeeded in filtering only the miscellaneous energy mixed in the soil.

Even though the Demon Realm wasn’t a good environment to live in, it changed the environment little by little. It ate the soil of the Demon Realm, which was close to chaos, and excreted soil containing pure miasma. In the process, the energy absorbed remained in him and changed its body little by little. The energy that helped it was absorbed from the inside to grow its body. The energy that was dangerous to absorb was transferred out of the body. A slimy fluid was flowing on its body, but its skin had already swollen violently. Anyone who touched its coat would have had a pretty terrible experience. It was a creature that was changing the entire Demon Realm without even realizing it.

The Devil took note of its existence, and intentionally put it in places full of energy. Since the Devil didn't like the way it looked, it was transformed into a snake-like form. The head, which had nothing, became a little pointed and had eyes; the bulging outer skin was turned into a hard crust. The changed Imugi finally gained the ability to think.

The Devil divided it into segments and scattered it throughout the Demon Realm until it devoured all the miasma in the Demon Realm and threw it up again. And when it was over, it was brought back together. By then, it had become strong enough to destroy a single world on its own.

The Devil put it in charge of eating whoever made it to the top of his prototype dungeon, and it remained coiled around the tower until Zero arrived.

Trivia

 * Zero called it an Imugi, but in fact, the monster wasn’t a snake, let alone a dragon.