In Total Drama All-Stars, Duncan is swapped to Mike's team after proving himself to be a hero instead of a villain in Saving Private Leechball. Although Duncan is often shown wanting to return to the villains, he behaves civilly towards his new teammates, including Mike. This may be due to the warm welcome party they throw him, which Duncan secretly appreciates. Overtime, Duncan notices that Mike's voice sounds "kind of familiar", but couldn't remember their history together until he hears Mike's evil alternate personality whistling In The Hall of the Mountain King. Duncan reveals to the audience in No One Eggspects The Spanish Opposition that he knows Mike from juvenile prison, and he was known then as a highly dangerous inmate named Mal. Realizing he and the other contestants are in serious trouble, Duncan tries to warn them of the truth, only for no one else to believe him except Mike's girlfriend, Zoey.
At the beginning of the episode, Mike seems genuinely happy to have Duncan on his team, celebrating his arrival along with Sam, Sierra, and Zoey. Duncan is annoyed by the gesture, thinking that Mike is plotting with the others to vote him off later, but accepts the cake. During the challenge, when Duncan denies cheering for Sam as he doesn't want to lose his "bad boy" status, Mike reassures him that "it's okay to be a team player". Duncan, however, looks at him strangely and notes that his voice sounds familiar.
In the woods, Duncan comes across Mal speaking to a blue harvest moon-affected bird and demands to know where he knows him from. Pretending to be Mike at the time, Mal tries to cover up by stating his past Total Drama experience. Duncan, however, doesn't buy it. Before he has a chance to figure out his identity, Mal sets the bird free. It scares Duncan so severely he runs off, as Mal laughs at his expense.
In the confessional, Duncan becomes distressed over his team's "heroic kindness" and thinks it may be rubbing off on him. He tries to prove he's still a "bad boy" by stabbing his knife into the wall, only to have the blade break. Mal then appears sarcastically wondering what happened to it. A flashback reveals that he stole Duncan's knife the previous night and crushed it with a rock. At the end of the episode, Duncan heard "Mike" whistling In the Hall of the Mountain King while on his way to Boney Island, during which their past finally hits Duncan. He reveals in the confessional that he and Mike were in juvie simultaneously, and the latter was called "Mal" at the time. Duncan then elaborates that he was "running the place" and is "bad news".
While Mike is still on exile, Duncan approaches Zoey and explains how he knew her boyfriend previously, as well as informing her about his evil personality. The lack of familiarity on Mal's end is explained by the fact that Duncan steered clear of him. During the challenge, Duncan and Zoey witness how Mal ruthlessly clobbers Izzy. They are further convinced that Mike is Mal when Izzy mentions Mal's name. That night, Duncan and Zoey consider the possibility that Mike is actually an alternate personality, while Mal is the real one. Duncan later states Mal was saved only because his own team could not vote.
- This is the second pair to have known each other in some way prior to the show, the other two being Katie and Sadie and Amy and Samey.
- This is the only pair of contestants to know each other that doesn't know about that from the beginning and weren't introduced together.
- Both of them were involved in a love triangle in the show which involved two females conflicting over them.
- Both of them have been the first contestant to be eliminated after the merge in a season.
- Both reached the finale in the second season they participated in.
- Both have theme music dedicated to them. While all of Mike's personalities have their own distinctive theme, notably, Vito shares the same theme as Duncan.
- Both of them, along with Chris, Beth, Lindsay and Izzy, have a known prison record.
|Interactions with||Everyone | Alejandro | Beth | Chef Hatchet | Chris | Courtney | DJ | Geoff | Gwen | Harold | Heather | Leshawna | Mike | Owen | Trent | Zoey|
|Other content||Guys' alliances | Scruffy|
|Interactions with||Anne Maria | Cameron | Duncan | Scott | Zoey|
|Other content||Mike's alternate personalities|