Kassim and Duncan met again in the 20th century, and Kassim told Duncan that Nasir Al Deneb, the descendant and true heir to an Arab throne was the last of his line and with no restored royal status he would not find a princess to bring the family back to Arab rule. There was one man between the heir and the throne, a dictator, Hamad.
Kassim told Duncan that he wanted him to kill the President, keeping his promise to render a favor. Duncan was very close to killing the president but pulled back and made the President promise him that the heir would never be harmed. The President promised, then quickly broke his promise, and killed Nasir Al Deneb, ending the royal blood line.Kassim felt betrayed by Duncan, and challenged him. Duncan refused to fight, and Kassim left. In order to make Duncan fight him, Kassim kidnapped Rachel MacLeod. When Duncan came to save her, he and Kassim fought. Duncan won the duel, but let Kassim live. Kassim left but promised he would return one day to kill Duncan.
It was later revealed in Kassim's Watcher Chronicle that the heir's mistress was found to be pregnant with his child, who would take over as the new heir to the house of Al Deneb. Kassim took the heir's mistress into his custody, where he would protect her and the heir's child until he was of age to again claim rulership.
Kassim used a Damascus scimitar with an ivory handled hilt. It appeared he had always carried a similar style blade.