Jiryū Sendō

is the leader of the Sendō clan.

Background
Jiryū formed the Sendō clan after the Howling Wolf Village declared its neutrality from all conflicts. He gathered together many of the village's former shinobi - left unemployed by the neutrality - and created a criminal gang that primarily dealt in saigenzai, a popular hallucinogen. Because of their saigenzai's poor quality, Jiryū wanted to learn how to make the special Kotarō sold by the Kodon clan. He and his clan would periodically harass Reishi and Kina Kodon to try and force them to turn over the secret to Kotarō. Itachi Uchiha, while visiting Reishi and Kina, would fend them off.

Appearance
Jiryū is in his forties and wears a black kimono with a white dragon wrapped around the hem. His head is shaved and his moustache has noticeable shades of white. According to Kina, he always smells like fish.

Naruto Jinraiden: The Day the Wolf Howled
In his continued effort to gain Kotarō, Jiryū and some of his men set fire to Reishi and Kina's shop/home. The fire is put out by Sasuke Uchiha, to Jiryū's disappointment. Although Jiryū and his men were not seen, Kina suspects his involvement and confronts him about it when he sees Jiryū a few days later. Jiryū denies responsibility and, goaded by Kina, has his men attack him. The men are easily fought off by Sasuke, who then takes Jiryū hostage. At Sasuke's instruction, Jiryū tells his men to put down their blue fire powder-loaded weapons. Sasuke releases him and warns him not to bother Reishi and Kina again.

A few days later, the Sendō clan is able to capture Kina, who they try to ransom in exchange for the secret behind Kotarō. Yet, shortly afterwards, Kina mysteriously escapes and the men who were guarding him are found dead. Because the men's injuries match several recent murder victims', Jiryū convinces the villagers that Kina is the murderer; he also builds on local legends by claiming that Kina is the ancient monster, Rōen. Jiryū leads the angry villagers to Reishi and Kina's home and they start destroying it with blue fire powder. Reishi tries to assert Kina's innocence, but the mob begins attacking him as well. Kina comes to his defence, and as the mob begins attacking him too, he unleashes Rōen upon them.

Jiryū is astonished that the story he made up is actually true. He instructs his men and the other villagers to attack it. The attacks don't work, but Rōen does eventually leave the area and starts heading towards the Howling Wolf Village. When Reishi and Sasuke try to follow, Jiryū and his men cut them off, offering to let them go after Rōen/Kina if they surrender the Kotarō. Because time is short, Sasuke sends Reishi on without him as he deals with Jiryū and the others. Knowing that Sasuke is temporarily blinded, Jiryū expects an easy victory for his men. The easy victory turns out to actually be Sasuke's, and Jiryū is too frightened by his skills to offer any further resistance.

Jiryū later witnesses Reishi giving his life to remove Rōen from Kina's body and seal it away. Sasuke confronts him and uses his Mangekyō Sharingan to rewrite Jiryū's memory: that Reishi was Rōen, and that Kina is the one who stopped him. At the celebration a few days later, Jiryū relates this story to anyone who'll listen, insisting to all that Kina is a hero.

Trivia

 * Written as 地竜, "Jiryū" means "herbal medicine prepared with dried earthworms".