Duckworth is completely devoted to his old employer, Scrooge McDuck, and his safety, to the point of terrorizing his enemies and family alike. Despite this, he was remembered fondly by both Ma Beagle and Flintheart Glomgold. He also seems to have a mutual antagonism with Scrooge's current housekeeper, Mrs. Beakley.
Dry-witted, dramatic, polite and devoted Duckworth is a jack-of-all-trades in the McDuck mansion, making him a favourite member of Scrooge's staff.
Duckworth was the butler and housekeeper of Scrooge McDuck. He was extremely loyal to Scrooge, and his favourite butler; he was known to throw the best parties, and was the one Scrooge always entrusted with planning out his birthday party. Duckworth died at an unknown point before 2017, and Scrooge stopped celebrating his birthday, convinced that no one else could throw a party as good and because he secretly missed Duckworth.
In 2017, when Huey Duck decided to throw Scrooge a party anyway, he hired an illusionist, Nik Nocturne, to entertain the guests. Nocturne was actually a Beagle Boy named Black Arts Beagle who was intent on causing mayhem and attempted to summon a demon from the Beyond to crash the party. Being rather inept at sorcery, he ended up summoning the ghost of Duckworth, who, taking advantage of the situation, pretended to be a demonic monster in order to chase away Nocturne and other enemies who had infiltrated the party.
Following these events, Duckworth was introduced to Huey, Dewey and Louie and the rest of the new inhabitants of McDuck Manor, and he resumed service as Scrooge's butler. This caused friction with Scrooge's current housekeeper Bentina Beakley, who had gotten used to running the house by herself.
Upon learning that Scrooge intended the whole household to participate in a game night, Duckworth made himself scarce, claiming that he sensed some ghostly disturbance that he needed to attend to. He ignored Beakley's pleas for him to stay, though he remained in the vicinity of the manor.
Duckworth can be seen in the present decorating the Mansion, as well as placing the star on top of the Christmas tree. In the past, he can also be seen making sure Scrooge is given standard information and properly dressed for business opportunities with some of his business partners who attended his Christmas party.
Duckworth had been taking a long-overdue vacation within the land of the dead for a week but was summoned back by Huey, Dewey and Louie, much to his anger. He then went into his Demonworth form and inquired as to why they had brought him back, with the triplets claiming they needed information on who he sold a particular lamp to during a yard sale Louie asked him to run.
When Della returns home, Beakley mentions among the things that transpired since she was away, Duckworth had died leaving Beakley herself to be the housekeeper. As he has not moved on far enough, Duckworth appears saying he needs to clean up some cobwebs in the underworld and a plate thrown by his successor goes right through him before he disappears.
After the Moonlanders capture most of Scrooge's allies, Duckworth decides they're all doomed and his time is better spent preparing their places in the afterlife before leaving through the floor. Mrs. Beakley takes note of the fact that he had to go down to do his task instead of up. Nevertheless, later that day he returns from the afterlife again and joins the rest of the group in their celebration for defeating Lunaris, as well as the duckburgians now befriending the Moonlanders. He then joins in on the group shot, unaware he and everyone else are being watched by the criminal organization F.O.W.L.
As a Ghost
Ghost Physiology: Due to having died prior to the series and became a ghost, Duckworth has all the standard abilities expected of a normal ghost.
Shapeshifting: One of his most used abilities is shapeshifting, with his most prominent transformation being a skull-face demon.
Intangibility: As a ghost, Duckworth is capable of phasing through walls.
Invisibility: Due to being a ghost, Duckworth can turn invisible.
Possession: Duckworth can temporarily possess and move objects, and presumably people.
Although Duckworth did not appear in the Carl Barks comics on which the TV series was based, Scrooge did have various irregularly appearing similar butlers in these stories, who went by such names as "Edgerton" and "Jarvis". However, there was not one consistent butler, and none of them appeared more than once.
Duckworth is the demon that appears in the introduction of the 2017 Ducktales reboot, though his identity is not revealed in the introduction following his premier episode