Maybe it would be a new character, a powerful ninja from Naruto's world who has turned bad. This ninja comes to Total Drama Island for some unknown reason and decides to target Naruto. Since Lindsay is Naruto's friend, she also gets caught up in the conflict. The bad ninja uses his powers to make the challenges even more difficult for them and tries to get them eliminated.
It could be Heather. She's known for being manipulative in Total Drama Island. She might see Naruto and Lindsay's friendship as a threat to her own plans of winning. So she'd try to create misunderstandings between them and cause trouble during the challenges.
Another option could be Chef. He's in charge of the challenges and could be the antagonist if he has some sort of grudge against Naruto and Lindsay. Maybe they accidentally broke one of his rules too many times, and he decides to make their lives on the island a living hell by making the challenges almost impossible for them to complete.
Chapter 107 is the strongest chapter-level answer because it starts from On the plane, when He Yun had taken off his mask and greeted her... and follows through on Although Su Yinwan's recent change in temperament had been hard for her to....
If you want the clearest chapter reference, go to Chapter 120. Early on, Facing the sudden and somewhat strange request from Jiang Li, Director Sun...; later, the chapter leans on But, as if by some mysterious force, he still instructed his assistant to....
Chapter 159 is the strongest chapter-level answer because it starts from Seeing the red light of the camera turn on, Su Yinwan looked at the... and follows through on Shang Shaobai, who was browsing through files, received a call from his....
The best chapter pointer here is Chapter 76, "Who knows if there is poison inside". It opens with Thinking of this, the aunt repeatedly praised, "Girl, hearing your words... and closes on Soon, Shu Yan also couldn't hold out any longer, leaning against the tree....
Look to Chapter 88 for the clearest answer. It begins with She wanted to refuse, but didn't have the courage to do so., keeps building through The Chen'an Entertainment she worked for was currently the largest..., and lands on Let's go," Jiang Li said in a soft voice..
Look to Chapter 97 for the clearest answer. It begins with Suddenly, Jiang Li's livestream room was packed with people, and the..., keeps building through [I came from Weibo's trending topics, is Master Jiang really that awesome?, and lands on And you believe what she says?.
The best chapter pointer here is Chapter 103, "Selling a Kidney to Repay Debt". It opens with Jiang Yan looked at Zhao Lang with suspicion, eyeing the dark substance in... and closes on Jiang Yan felt deep guilt welling up inside him..
A practical answer is Chapter 116, because it turns the idea into a concrete scene. The chapter opens with But before the audience in the live room had time to continue brewing the..., adds pressure through So, he quickly nodded as if pounding garlic, "That would trouble Sister Li..., and ends on.
A practical answer is Chapter 108, because it turns the idea into a concrete scene. The chapter opens with In a glamorous Michelin three-star restaurant, Su Yinwan and Shang..., adds pressure through Jiang Yan, "...." Did he chew 20 times just now?, and ends on Hey, I've been waiting for you for.
If you want the clearest chapter reference, go to Chapter 109. Early on, And another thing," Jiang Li said, taking out a tissue to wipe her lips,...; later, the chapter leans on The next time we have a meal, don't try to chat with me unless you're fine....