Lord Manfred Dargis is the main antagonist of Garfield: A Tail of Two Kitties. He is also the nephew of Prince's former owner who wants to get rid of Prince. If Prince was to die, Dargis would inherit the entire estate.
Dargis is power hungry and wants to inherit Carlisle Castle from his aunt. But in her will, she left it to her cat Prince XII, which made Dargis jealous and angry. To get rid of Prince, Lord Dargis kidnapped him by trapping Prince inside a picnic basket and threw him off a river that led into a sewer, although a crow notices this and reports to a ferret named Nigel that Dargis has got rid of Prince which prompts Nigel to tell the horrifying news to the barn animals. However, Prince's servant Smithee found out that Prince was missing and told Dargis this when Dargis was busy shooting ducks. Later, Garfield, the protagonist of the movie, was found by Smithee, who mistakes him for Prince due to his very similar appearance. Meanwhile, Dargis was showing a representative named Abby Westminister whom he was dating, that he plans to get rid of all woodland in the estate, develop industry, and have tourists dine on the barn animals as he plans to get rid of any available space for them to live in so he can make buildings for more profit. However, a rat named Claudius overhears this and goes to warn the animals of Dargis' plan. Afterwards, he was throwing darts at a picture of Prince when the phone rings with Dargis' lawyers on the line. As Dargis talks to his lawyers, he failed to notice McBunny place a mousetrap next to his darts when he isn't looking. When Dargis hangs up and reaches for another dart, the mousetrap snaps his hand which causes him to scream in pain.
Later, Dargis trained Carlyle Castle's guard dog, a Rottweiler named Rommel to become vicious and to slaughter Prince. However, unknown to Dargis, Prince's dog servant Winston turns the tables around by forcing Rommel to play a game of tug-a-war with Dargis's new trousers. Having turned over a new leaf as he has now become obsessed with trousers, Rommel tracked down Dargis, but while the latter is talking to Abby on the phone, Rommel attacked him at the groin to which Dargis shouts in pain.
Dargis was next seen at the pool, where he becomes furious upon seeing lots of animals there and started chasing a dog until he tripped over a pig. He was then seen complaining to Smithee and got knocked out by a rake placed by Winston while he was complaining. Later, Dargis trained Rommel to eat Prince and now wears a tasset for safety in case if he tried to attack him again. He succeeded in getting Rommel to rip apart Prince's portrait while using meat as bait, but this was seen by Smithee in which Dargis feigns innocence and accuses Rommel for ripping apart Prince's portrait. He then graciously gives Smithee a holiday for a week. Meanwhile, Garfield and Prince eventually meet up and Garfield claims that the animals must set up an attack to save their home and prevent Dargis from becoming the new lord of the castle.
They taunted him many ways such as slamming a piano lid on his fingers, knocking him out with a shield and allowing Rommel to chase him down due to his obsession with trousers. But the plan becomes a failure, and Dargis forces the Carlyle Castle Council to sign the castle's deed over to him while threatening to kill them with a bow and arrow. The council quickly try to write the deeds to him to live, and Dargis even betrays Abby when she reveals to have been working for Mr. Hobbs. Garfield and Prince both show up, making Dargis stunned when he figured out that there are two cats that look exactly the same.
Garfield's owner Jon Arbuckle and his canine friend Odie arrive in which Odie bites Dargis, causing him to throw away the bow and arrow, although Jon manages to catch it. When Dargis grabs Jon's girlfriend Liz next to him, Jon orders and threatens him to let her go, but Dargis manages to grab a gun at the moment. After Dargis turns the tables on Arbuckle, Garfield orders Nigel to climb into Dargis's trousers. Dargis becomes frustrated and tries to get Nigel out of him, but Jon knocks Dargis unconscious by punching him in the face. Smithee calls the police and arrests Dargis for his actions, while Dargis is relieved as he is certain that Smithee will vouch for him (despite Dargis' mistreatment of him) while the group celebrate by having a pool and barbeque party.