Who could be the main antagonist in 'Teddy Lupin meets his father fanfiction'?

It could be a rogue Death Eater who escaped justice and is now seeking revenge on the Order and anyone related to them. So, Teddy, being Lupin's son, would be a target.

In this kind of fanfiction, perhaps Teddy Lupin discovers a magical way to time - travel and meets his father. It could show Teddy learning about his father's character and values through their interactions. Maybe his father teaches him some unique magic that was passed down in the family.

Well, aside from Teddy and the Marauders, there could be other characters as well. Maybe some of Teddy's friends or classmates from his own time who are somehow involved in his journey to meet the Marauders. For example, if Teddy discovers a time - traveling spell in the library with the help of a studious friend. But the core characters would still be Teddy Lupin and the Marauders. Teddy is the link between the present and the past in this story, and the Marauders are the ones with all the stories and experiences from their time at Hogwarts.

Well, Teddy might be shocked by the Dursleys' coldness at first. He could show them some magic in a very subtle way, just to see their reactions.

Well, it could be about Teddy Lupin traveling back in time and meeting his father's friends, the Marauders. Maybe he gets to experience their pranks first - hand and learns some new magical tricks from them.

Well, Teddy could learn a great deal about his family's history from the members of the Order. Maybe he'd discover some hidden secrets or untold stories.

It could be a demon who has a grudge against Kagome's father. Maybe her father defeated this demon long ago, and now that Kagome is in the picture, the demon sees it as a chance to get revenge on the family.

Well, one possibility is that Teddy, being the son of Remus Lupin, would likely be filled with a sense of justice. He might immediately be on guard around Umbridge. Since Umbridge was known for her cruel and unjust ways at Hogwarts. Teddy could use his Metamorphmagus abilities to play tricks on her, like changing his appearance to something that scares her when she's being particularly mean.

It could be one of his professors. If Teddy was constantly late to class or not doing his homework, a strict professor like Professor McGonagall might send a Howler to set him straight.

It could be Frieza. Since Frieza has a history of hating the Saiyans, he might see Goku's sister as a new threat and try to eliminate her.