Every Total Drama season has an antagonist. Some of them are good, Some of them are bad. Although there have been quite a few antagonists, what makes a good antagonist?
Most people consider the six Main Antagonists to be: Heather, Courtney, Alejandro, Scott, Mal, Sugar
Although I am only speaking for myself and not the fandom, I would say that only three of the six people listed are actually antagonists (Heather, Alejandro, Scott). Those three have caused eliminations, played manipulatively, formed alliances, etc.
Courtney, Mal, and Sugar have done none of these, except for Courtney attempting to form a female alliance with Beth. Mal mostly broke stuff and tried to mess with Zoey's head. Sugar held a grudge against Ella and finally got her eliminated, and Courtney mainly just complained and forced Chris to rig the game for her.
Although Sugar and Courtney are considered to be the main antagonists of Action and Pahkitew, there are other options to go with when it comes to the antagonist of the season. Action has Justin. Justin didn't do much, but he clearly tried to work with Lindsay and Beth, which goes with the alliance thing, and he pretty much caused the eliminations of Trent and Gwen. Pahkitew has Amy, Scarlett, and Max. Although there are three options, Amy only bullied Samey throughout her run, and Max was just a comic-relief anti-antagonist. Scarlett didn't do anything until her elimination episode, and all she did in that episode was nearly the same as Courtney in Action and Heather in her Revenge cameo (Try to take control, take the money for herself in an unfair way).
Going back to Heather, Al, and Scott: Heather did many antagonist-like actions in Season One. She formed an alliance with Lindsay and Beth, Used that alliance and had Owen and Izzy vote with them to eliminate Justin. Managed to steal Eva's MP3 Player and turn her whole team against her, resulting in her being voted off. Kissed Trent in front of Gwen, leading to LeShawna finding out and asking for votes against Trent, and finally ditched Lindsay in the Bike Race and got her booted off. Alejandro pretended to flirt with Bridgette and LeShawna, leading to their eliminations. He also had something to do with Noah's boot. Scott blossomed the idea of Dakota leaving in Week 2, but that isn't too villianous, considering it was just asking for votes. He also held a big part in B's elimination. But the biggest elimination, (and the most constroversial) he caused was Dawn's. He planted everyone's valuable things in her garbage bag, and framed her for stealing everyone's things, resulting in her being voted off.