- "Yes, do as Mummy says. Why don't you ask that tailor friend of yours to knock up a nice chicken costume. It'll suit you, you mug."
- ― Dean to Eggsy after Eggsy starts to head for the pub doors.
After losing her original husband Lee, Michelle Unwin some time later met Dean and fell in love with him, eventually marrying him and having a baby with him (Daisy). Unfortunately, Dean was very abusive to Michelle, her son Eggsy and Daisy but didn't leave him because of how she had low self esteem. He even had a gang that also went after Eggsy.
While Dean was on the couch watching TV with Michelle, he asked Eggsy to get some Rizlas. After Eggsy refused and tried to get him to get Dean's poodle to do it, Dean made Eggsy get the Rizlas while continuing to kiss Michelle on the couch. Rottweiler (the leader of his gang) later called Dean after Eggsy had stolen his car and then called him again the next day that Eggsy was in the bar with a man (Harry Hart) who beat them all up when they attempted to beat Eggsy over the stolen car.
When Eggsy returned home, Dean ambushed him, beat him up and tried to interrogate him on the man responsible for attacking his gang, but Eggsy didn't give in. Dean then threatened to kill Eggsy with a meat cleaver, but is saved by the timely intervention of Harry, who placed an undetectable bug on Eggsy's vest in the form of a tiny microphone. Perplexed as to where Harry's voice is originating, Eggsy escaped Dean's grasp and fled.
During the several months that Eggsy spent away while training to be a member of the spy organisation Kingsman, Dean abused Michelle further and gave her a black eye. Eggsy tried to confront Dean about it at the Black Prince, but Eggsy's car, which was in fact Harry Hart's, drove away when Harry used a device to remotely control it. This led Dean to accuse Eggsy of being a coward for running away and to yell at Eggsy to "come back once [he'd] grown a pair".
Towards the end of the movie, Dean chastised Michelle for her playing the song "A Slave To Love" when they were both in the Black Prince with Dean's men. Eggsy then came in, dressed in a smart suit and saying that he'd just got a job at a tailor shop on Savile Road, adding that he also had a house with it. With this, Eggsy offered his mother a new home away from Dean, but Dean just ordered Michelle to sit down, while he rose to try and threaten Eggsy. Although Eggsy seemed to do so (while Dean made a mocking comment about getting a Chicken costume made for him), Eggsy was actually moving to lock the bar doors, all the while mimicking Harry Hart's comment that "manners maketh man". After Eggsy did so, Rottweiler attempted to warn Dean, but he wouldn't listen and continued to threaten Eggsy until Eggsy used his umbrella handle to hook a beer glass, which flew at Dean and knocked him out.
It is implied that Michelle and Daisy left Dean to live with Eggsy after the brawl at the bar.
Dean is a foul-mouthed and cruel middle-aged man who not only violently inflicted abuse on his wife and step-son, but also believes no one is allowed to mess with him, which explains his behavior when attempting to find out who assaulted his gang in the pub. He is more than likely an alcoholic, which could be a contributing factor to his violent behavior. He was willing to murder Eggsy in order to find out who attacked his gang in the pub. It is also likely that he married Michelle for her first husband's money, hardly showing any romantic feelings for her.
Aside from his lack of familial love (especially for his daughter), he also shows little interest towards his gang due to being egotistical; even when his gang learned that Eggsy had become a skilled Kingsman and warned Dean not to mess with him, Dean angrily told them to shut up, only to end up being knocked down by Eggsy himself.
- Gary "Eggsy" Unwin - Stepson