Obviously, a Potter and a Weasley would be the main characters. It could be Albus Potter and Rose Weasley, for instance. They would be the ones most directly affected by the feud between their families.
Another possibility is that it could be descendants of other Potter and Weasley family members. Maybe a distant cousin of Harry Potter who has grown up hearing only the bad things about the Weasleys, and a Weasley who has been taught to be wary of the Potters. These two characters could start out as enemies but gradually change their views as the story progresses.
Well, it could start with an old, long - forgotten grudge between the two families. Maybe a misunderstanding in the past regarding magic or a family heirloom. For example, a powerful magical item that was thought to be stolen by a Potter from a Weasley ancestor, which led to the start of the feud.
Obviously, Harry Potter himself could be a central character. He might be drawn into the blood feud because of his reputation and his desire to maintain peace in the wizarding world. He could try to mediate between the feuding families.
It could be a long - lost relative of Voldemort. Maybe a distant cousin or something who has the same thirst for power and has decided to target Harry and his friends to gain more influence in the wizarding world.
It could involve Harry Potter taking a stand against a dark wizarding family that has wronged his loved ones. Maybe they've targeted his friends or family, and he decides that a blood feud is the only way to deal with their ongoing threats and attacks.
It could be a long - lost relative of the founders. Maybe a distant cousin of Gryffindor, Ravenclaw, Hufflepuff and Slytherin. This person might have been hidden away for years and now resurfaces.
As I haven't had the chance to read 'the feud short story', it's difficult to determine the main characters. But generally, in a story about a feud, you might expect to find the instigators of the feud. They could be people with a long - held grudge, perhaps due to a past event that affected their pride or livelihood. There could also be characters who are trying to reconcile the two feuding sides, like a mediator or a relative who wants to see peace restored. These could all potentially be main characters in the story.
A werewolf might be a great main character. He is cursed and during the blood moon twilight, he has to struggle to keep his humanity while also protecting his pack from hunters who are more active during this time.
Obviously, Harry Potter himself is a central character. There could also be members of the families involved in the blood feud. For example, if it's a feud between two pure - blood families like the Malfoys and the Weasleys, we would expect to see Draco Malfoy and Ron Weasley in the story. And of course, Hermione would likely be by Harry's side, using her intelligence to help him figure things out.
Obviously, Harry Potter himself is often at the center of it. His friends like Ron and Hermione might also be involved as they support him through the family drama.
It could be a long - lost descendant of the founders of all the houses. Maybe a distant relative of Godric Gryffindor, Salazar Slytherin, Rowena Ravenclaw, and Helga Hufflepuff. This character would be in a unique position as they have the blood of all the great wizards and witches who founded Hogwarts.