He was notorious for leading the Lost Heritage crime-gang. Like the rest of the gang, he had had illegal genetic modifications.
Stavan was reclusive, and claimed to be a descendent of Khan Noonien Singh, the genetically enhanced human tyrant. As Stavan was an Orion with emerald skin, this was considered dubious at best. (Last Unicorn RPG module: Star Trek: Deep Space Nine Core Game Book)