He is a bald man who wears a monocle over his left eye.
A calm and serious individual. He is also amoral and willing to euthanize members of his group if they failed him.
He was the supervisor for the Group of Terror, but unlike Gozuki, he would treat the five inhumanely, locking them up when they didn't succeed easily. After their first mission turned out to be disastrous, Gozuki euthanized Remus due to her being the weak link of the group.
Much later, Akame would assassinate him and his assistant, though Uncle Bill would attempt to attack by buffing up to a stronger form, only to be killed instantly.
Equipment & Skills
Bill is well versed in various medical and pharmaceutical fields, as seen where he successfully created various performance-enhancing drugs to enhance the physical and mental abilities of his assassins. Its also been implied that Bill himself was also capable of various other drugs, such as truth serum.
Bill himself was implied to have been an active researcher in developing various drugs, this is seen where after his death, the Empire had managed to successfully collect his research in order to continue his work.
Bill was also well versed in brainwashing and mental conditioning techniques, as it was revealed that he was the one responsible for placing the powerful mental suggestion into the members of the Group of Terror not to betray or abandon the Empire and doing or even thinking of doing so was absolutely wrong. These mental suggestions was so powerful that not a single one of his "soldiers" ever questioned or resisted it and even if these notions were ever considered, it would cause severe pangs of pain on them. These techniques was also eventually used on their successor group the Dark Squad on the new members acquired and recruited by the Empire.
For actual emergency combat Bill also had a drug secretly hidden in his molar that when ingested enhances his physical power and causes him to bulk up into a large muscular form.