Deragar is a Jhereg working for Kragar as a lieutenant in his territory near Malak Circle in Adrilankha, that he took over from Vlad Taltos. Among close friends and family, his name is often shortened to "Derr".
During the events of Hawk, Kragar assigned Deregar to assist Vlad and help watch out for him, as the Jhereg Organization was still trying to have Vlad killed at the time.
This duty was performed successfully, and Deragar aided Vlad several times to prevent the Jhereg from completing their plans.
It was later revealed that Deragar was also Kragar's son.
Shortly afterward, when Vlad was hiding out in The Crying Clown theater. Deragar began an investigation into which specific members of the Left Hand of the Jhereg were after him. During this investigation he was drugged, captured and held for ransom in exchange for Kragar revealing Vlad's location.