There could also be a legal trial of sorts within the wizarding world. If the evidence of Harry's abuse is strong enough, the abusers could be sent to Azkaban or some other form of magical prison as punishment for their actions.
They could face expulsion from the wizarding community if the abuse is severe enough. The wizarding world has its own laws and rules, and abusing a young wizard like Harry would be a serious offense.
If the champions decide to take matters into their own hands, they could use magic to teach the abusers a lesson. For example, they could jinx the abusers so that they are unable to harm Harry again. However, if they report to the school, the abusers might face a formal hearing. Depending on the severity of the abuse, they could be banned from certain areas of the school, lose house points, or even be permanently removed from Hogwarts. There could also be social consequences, like being shunned by other students.
In the fanfiction world, the abusers may find themselves ostracized by the wizarding community once Viktor reveals what they've done. If Viktor has friends or allies in high places, they could ensure that the abusers are held accountable for their actions. There could also be legal consequences within the wizarding laws if the abuse is of a certain nature. For example, if it involves dark magic or illegal forms of coercion, the abusers could be sent to Azkaban or face other forms of severe punishment.
Sirius might use magic to punish them. He could hex them or use some other form of magic to make them feel the pain they inflicted on Harry.
The abusers might be ostracized by the community. Once Triton finds out and spreads the word, other sea - creatures or characters in the story might shun them. This could lead to them being isolated and having a hard time getting help or resources.
Fleur might expose them. If they are students, they could face expulsion from Hogwarts.
They might face magical justice. In some fanfictions, the Ministry of Magic could get involved and strip them of their magic, or at least put them under strict surveillance.
One possible consequence could be that Harry becomes withdrawn and distrustful. He might have difficulty forming relationships with others, always fearing that they will also be cruel like his parents. He could also develop low self - esteem, constantly believing that he is unworthy of love and care because of how his parents treated him.
They could also face legal consequences in the wizarding world. There are laws in place to protect the rights of wizards, and abuse is likely a violation of those laws. The Ministry of Magic might get involved, and the abuser could be sent to Azkaban or face other forms of punishment depending on the severity of the abuse.
Narcissa might be very angry with Harry's abusers. If it's the Dursleys, she could use magic to give them a taste of their own medicine, but in a more subtle way so as not to draw too much attention. For example, she might make their houseplants grow out of control or cause their food to spoil every time they're mean to Harry.
The abuser could face magical justice. In the wizarding world, there are probably spells or enchantments that can be used to punish wrongdoers. James Potter might use his connections to ensure the abuser is dealt with severely, like being sent to Azkaban or having their magic restricted.