Ungai

is a monk known by Miroku. He discriminates against all yōkai and could be considered a bigot. Not understanding the relationships between Sesshōmaru and Rin, and Inuyasha and Kagome, Ungai tries to warn Rin against following Sesshōmaru but she rejected it, for her friendship to Sesshōmaru. He cannot understand why.

History
Ungai was the leader of a group of Yōkai hunting monks. As he and his men met Inuyasha and his friends, he first showed his disapproval about the fact that Shippō and Kirara were among them. He was not assured when Miroku and Sango claimed that the two would never do something evil, but refrained from fighting, although he warned them not to get in his way.

Later, he and his men were on the hunt for Ongokuki, a Yōkai who kidnapped children. Among the abducted children was Rin, who was lured away by the Yōkai from her camp. Ungai and his followers were able to defeat the yōkai. Then Sesshōmaru appeared, Rin ran to him, but Ungai did not want her near a Yōkai, and prevented her from approaching him. Shortly thereafter, there was a struggle between Ungai's people and Sesshōmaru. Sesshōmaru was able to defeat them fairly easily. Sesshōmaru told Rin that she could decide for herself whether to stay at his side. To Ungai's dismay, Rin decides to follow Sesshōmaru.

When he and his men picked up the reward for the destruction of the yōkai and saving the children, he met Inuyasha's group again. He noticed Inuyasha next to Kagome and asked her why she was in the company of a yōkai. She initially did not reply, but he resigned his question, and said that he would rather not want to know the answer.

Personality
According to Miroku, Ungai is merciless against all yōkai, even ones that do not hunt humans. He criticized Miroku as being unprincipled for keeping demons with their group, calling Kirara an evil spirit and warning them that if they rely on something like that they'll only regret it. He didn't believe that Kirara and Shippō did not harm humans. He also believed it was foolish for humans to use a demonic weapon as it would kill them.

Ungai is not a cruel or violent man, he has repeatedly show kindness to humans, and did not attack the demons in Miroku's care or take the Tessiaga from the then-human Inuyasha even though he probably could have. But when Rin said she wanted to be with Sesshōmaru he didn't believe her and restrained her. At one point, he even said that humans and demons lived in different worlds. It's likely that a lifetime of fighting demons and seeing the damage they cause has caused him to be unable to see demons as anything other than violent or preparing to be violent.

Powers & Abilities
As a well known monk who also hunted all kinds of Yōkai, he was considered extremely powerful. Considering he was able to harm Sesshōmaru, the most powerful demon in the series, his reputation is well deserved.
 * Vajra: He threw a gold vajra at Sesshōmaru. Although it did not hurt him, the resulting explosion leveled a fair amount of the forest.
 * Rosary: Working in conjunction with the other monks, he would raise his rosary to paralyze a demon.
 * Staff: He could unleash a large amount of spiritual power through his staff at a demon to destroy them. While it did not visibly harm Sesshōmaru, it did stagger him to the point where he gripped Tōkijin. Sesshōmaru was forced to partially return to his demon form and use the energy from the transformation to break free, shattering Ungai's staff.

Trivia

 * Ungai only appears in the anime.
 * When Ungai first meets Inuyasha (during the night of the new moon), he warns him against using his demon sword. Despite their animosity for each other, they both share the belief that humans should not be in possession of demon weapons.
 * His name, which means "clouded view", fits him very well.

Ungai 云涯