Tongue Demon

The Tongue Demon is a brawny figure with grayish skin and very dark blue hair pushed unusually high on the skull, leaving space for the pair of small horns at its temples. It has two sets of eyes: a larger, feline green pair below, and a narrower red-irised pair set above them.

Its defining trait is an enormously long tongue. Navy markings shaped like arrows run across its nose and forearms, with matching blotches at each temple. It wears nothing on its upper body, clad only in the lower half of a patterned, knee-length yukata.

Like many of its kind, the Tongue Demon is a savage being fixated entirely on devouring any human it encounters. It seems dull of mind, muttering to itself and echoing its own words, and it tends to crawl along the floor rather than walk upright. Even so, it is bold enough to brawl with Kyogai and a much bigger demon, all three squabbling over who gets to eat a Marechi-blooded boy.

Before Tanjiro Kamado and Zenitsu entered the residence, the Tongue Demon learned that the mansion's master demon, Kyogai, had captured the boy Kiyoshi for his rare Marechi blood. A third demon joined the dispute, and the three quarreled over who would eat him. During the struggle a tsuzumi was torn from Kyogai's body, and Kiyoshi seized it to teleport away, scattering the demons through the halls in search of him.

While creeping about, the Tongue Demon comes upon Zenitsu and Shoichi, Kiyoshi's younger brother, in Episode 12, chasing them into an empty room. Paralyzed by terror, Zenitsu faints, baffling the demon. When it strikes at Shoichi with its tongue, the tip is sliced off without it noticing. The unconscious Zenitsu then acts on instinct and beheads it with Thunder Breathing, First Form, before waking with a start beside its severed head.