For the death knight in Heroes III, see Clavius.

""Clavis...," Alagar said, watching him warily. "Clavis is one of Sendark's Death Knights," he told the others. "Be careful around him. He's as deceitful as he is dead.""
Clavis is a death knight that appears in Might and Magic: The Sea of Mist. He was old and withered, and the shrunken skin on his skull and hands made his yellowed eyes bulge fiercely. He wore black and gold armor. He was usually polite and curteous, bowing deeply and taking insults with a smile, but he was always dangerous.

When he was alive, Clavis had been a knight sworn to the dark gods. When he died, he had been resurrected by Sendark, who made sure that Clavis kept his skills as well as his mental abilities. At the time of the attack on Soronne, Clavis had served his master for 300 years.

After the first strike on Soronne, Clavis was sent to the Isle of the Dead to keep an eye on Fahd Mandel and Commander Lenik, the two traitors who had aided Sendark in his siege. Clavis informed his master that during the battle, one of Soronne's defenders had killed almost half of Clavis' army single-handedly - a young warrior named Praz-El. Clavis believed he would be a great asset, and since Praz and his allies were now traveling to the Isle of the Dead as well, Clavis wanted to kill him and raise him. Sendark agreed.

Clavis visited Mandel and Lenik in the keep on the Isle of the Dead and told them that Sendark was worried for their safety. He had been sent to set up patrols around the island and keep them safe. The two traitors knew that Sendark wasn't concerned about their well-being, and that Clavis had most likely been sent to spy on them, but since they had grown so powerful that they no longer feared Clavis or his master, they allowed it.

As Mandel and Lenik began to search for the magic fountain inside the mountain, Praz and his group destroyed one of Clavis' patrol ships. Sensing a great tremor of magic, Sendark contacted Clavis and asked him what had happened, and the death knight informed him that Praz had single-handedly torn the ship to bits. Sendark learned that Praz was the foster son of Magistrate Bo, who had recently been killed and brought back as one of Sendark's zombies. He asked him about the boy, and from what the zombie told him, Sendark realized that Praz was the son of Daria and an unknown god of darkness.

Clavis was now on his way to the beach to kill Praz and his allies, but Sendark realized how valuable the young warrior could be, and told Clavis to aid them instead - help them to find the secret path into the mountain so that Praz and the others could face off against Mandel and Lenik. Clavis approached Praz's group and told them that Mandel and Lenik had betrayed Sendark as well. He offered to show them the path to the fountain if they handled the fighting. The heroes knew they couldn't trust him, but they were running out of time, and might not find the two traitors on their own, so they agreed. Clavis smiled and showed them the secret entrance.

When Praz and the others emerged victorious, Clavis was nowhere to be seen.