The Blood Lord

The Blood Lord is a crime boss that appears to be involved in various crimes around Denerim. They appear to have a few people working for them including the Brigands that accosted Fabian and Elissa Cousland in the alley.
They also appear to have Decker working for them and at least assisted in getting him out of jail.
Captain Oakland believe that Elissa was actually the Blood Lord although later changed his mind as he decided to allow Elissa out of prison after paying bail.