Voldemort could be an antagonist. Even if Tom is a character in the marriage contract, Voldemort's ideology and his followers might oppose the union as it could potentially change the power dynamics in the wizarding world that they are trying to control.
The pure - blood supremacist families could be the main antagonists. They might see the marriage between Harry and Tom as a threat to their long - held beliefs about blood purity. They could try to stop the marriage contract from being fulfilled by any means necessary, including using dark magic or spreading false rumors.
The Ministry of Magic could be an antagonist in this fanfiction. They might be worried about the implications of such a marriage on the wizarding society. They could try to interfere with the contract, fearing that it could lead to unrest or a change in the established magical order. For example, they might try to arrest Harry or Tom under false pretenses to prevent the marriage from taking place.
Well, it could be an old enemy of Harry's who doesn't want to see him happy in this new relationship. Maybe a dark wizard who wants to disrupt the peace that the marriage might bring. Another option is a jealous rival of Susan's. Someone who had feelings for her before and now is enraged that she's in a marriage contract with Harry.
One possible plot twist could be that the marriage contract was actually a ploy by an enemy to divide their wizarding families. Maybe the terms of the contract were misinterpreted at first, and as they start to fulfill it, they discover hidden clauses that put them in a difficult situation.
The pure - blood family that arranged the marriage contract could be the main antagonist. They might have a lot to lose in terms of status, power, or wealth if the contract is broken. So, they would do everything in their power to force Harry to uphold it, even using dark magic or underhanded tactics.
The main characters are Harry Potter and Draco Malfoy, of course. Harry is the famous 'Chosen One' who has fought against Voldemort. Draco is from a pure - blood wizarding family, and has often been in conflict with Harry at Hogwarts.
Well, obviously Harry Potter is one of the main characters. He is the famous wizard who defeated Voldemort and is now thrust into this unexpected situation of a marriage contract.
The Ministry of Magic could be the antagonists. Since Harry is in a gang, they might see him as a threat to the order of the wizarding world. They could send Aurors after him and his gang mates, trying to arrest them and break up the gang.
The Ministry of Magic officials who strictly enforce the marriage law could be antagonists. They might be so bent on following the rules that they don't consider the individual feelings of Charlie and Hermione. For example, an overzealous bureaucrat who keeps checking on them to make sure they are fulfilling their marital duties according to the law.
Well, the two main characters are Harry, who has an 'evil' side in this fanfiction, and Daphne. But there might also be other supporting characters. For instance, Daphne's family members could play important roles. They might be concerned about her being in a marriage contract with an 'evil' Harry and try to influence the situation. Or there could be Harry's allies or enemies from his past that come into play because of this new development in his life with the marriage contract to Daphne.
One possible character could be the person he is supposed to marry according to the contract. This character might be from an old wizarding family, and they could be initially angry or disappointed with Harry's refusal. Another character could be Harry's best friends like Ron and Hermione. They would likely support Harry in his decision, especially Hermione who is a strong advocate for free will and individual choice.
Voldemort or his followers could still be antagonists. They might not like the idea of Harry being under Euryale's protection as it could make him more powerful. Another possibility could be some creatures from Euryale's world who are against her taking in an outsider like Harry.