Numawatari

was a yōkai who insinuated itself in ponds devouring everything that was in, or near, humans, animals, fish and birds. Even the water was eaten and at the end Numawatari himself became the pond. He migrated from one pond to another.

History
The first people to approach the turbid pond of Numawatari were Rin, Jaken and Sesshōmaru. Rin was thirsty and wanted to drink from the pond, but Sesshōmaru stopped her, then seeing a bird that got devoured.

Inuyasha's group goes to examine the pond after being informed by the villagers of the village. Inuyasha used his Kaze no Kizu on the pond to flush out the yōkai. Numawatari, while controlling the water, created vortices and shape of his face. Inuyasha tried to attack him with the Bakuryūha and the Kongōsōha, but both techniques were ineffective because the yōkai was made of water.

Only the Dragon-Scaled Tessaiga had an effect on it by absorbing the yōki of Numawatari, but the demonic energy was too large. Miroku tried to absorb all the water with the Kazaana, but he was forced to stop because the water was likely to remain tainted by the aura malignant.

At this point, Sesshōmaru, outraged by the way in which Tessaiga was used by his brother, killed Numawatari with Meidō Zangetsuha, still incomplete, sending him and all the water in the underworld, after having defined the water yōkai as weak.

Powers & Abilities
Numawatari was made of water, making it invulnerable to most attacks.