Shōki

Naraku's miasma.

Shōki (瘴気（しょうき）, "Swamp Gas"), or "Miasma" ("Bad Air") in the English dub, is highly corrosive and poisonous gaseous mist, a purple, smoke-like form, used by many demons as a means of both attack and/or defense. The jaki of any yōkai who can generate a miasma is also present in their miasma, like as in a unique signature. The more potent one's jaki, the more powerfully corrosive their shōki/miasma becomes.

Naraku made widespread use of potent and lethal miasmas, using it to deliver his Jaki and destroy organisms in large vicinities.

When Sō'unga reanimated its victims, their corpses were filled with miasma.

As the Kongōsōha have been combined with the miasma since Mōryōmaru absorbed Naraku, he used it to attack it. Since the fragment of Kanna's Mirror demon have been placed on Sesshōmaru's Tenseiga, that Naraku can control it effortlessly as he used Kongōsōha with the miasma on Inuyasha.

In Hanyō no Yashahime, the Grim Comet and the Grim Butterfly can produce intense waves of miasma.

Trivia

• The term Shōki in myth and the supernatural refers to ki/qi of a malign influence which is often considered to be avoided and dispelled, particularly with the arts of Feng shui and Onmyōdō. Due to Shintō's adaptable syncretization with other religions and beliefs, Shōki is also related with demons and the state of kegare due to its corrupting and foul nature.