It will be finished as soon as possible. We're working as fast as we can, sheesh!
Tesso (鉄鼠, Iron rat) is a rat yōkai.
Due to the fifth anime adaptation's sudden cancellation at 100 episodes, he is among the 23 Yōkai Warriors that were not revealed aside from the movie.
Steel Skin: Tesso is able to make his body as hard as steel.
Sharp Claws: He has rather sharp claws that are capable of tearing and shredding almost anything.
Tesso is the form that a monk named Raigō took after dying from a hunger strike. During the Heian Era the monk Raigō, the abbot of Mii-dera, was asked by Emperor Shirakawa to pray to the Japanese gods and Buddha to help him obtain an heir. Eventually, after praying for so long and hard, the Emperor had a son named Prince astafumi. The Emperor was grateful and promised to give Raigō anything he wished for, his only request was to have his own monastery in Mii-dera so he could train new priests. The Emperor agreed but was unable to do so, due to the pressure of the rival monastery, Enryaku-ji, where warrior-monks lived.
Because the Emperor could not fulfill the promise, Raigō began a hunger strike, eventually passing away. Filled with rage, Raigō's spirit came back for revenge, first by killing the Emperor's son. Afterwards, he took the form of a giant rat, who's body was hard as stone and its teeth and claws as strong as iron, soon to be called Tesso, where it summoned an army of rats that swarmed down on Enryaku-ji and ate everything the monastery owned. Nothing could stop its wrath until a shrine was built at Mii-dera by the Buddhists, to appease Raigō's spirit, it was placed in the north facing in the direction of the Enryaku-ji.