The Vorta who runs the Dominion prison camp where Worf, Garak, Bashir and Martok are held.
Deyos is the Vorta in charge of Internment Camp 371 in By Inferno's Light. He uses Worf as a sparring partner for his Jem'Hadar guards, sending them against the Klingon one after another.
When the Jem'Hadar commander Ikat'ika concedes his fight with Worf out of respect, Deyos is disgusted and orders both of them executed. Garak activates the prisoners' transmitter just in time, and the captives are beamed away before the order is carried out.