Harry Potter could be one of the main characters. He might be the one who discovers Draco in this strange situation and has to decide whether to help him or leave him be, given their past rivalry.
One possible plot could be that Draco is in a situation where he is being controlled by a leash for some magical or political reason. Maybe he's being paraded as a symbol of a new order in the wizarding world. His former Slytherin pride is put to the test as he has to endure this public display.
One character could be Viktor Krum. Since he is from Durmstrang, he might play a role in Draco's new life there. Maybe he becomes a mentor to Draco or a rival in some magical competitions at the school.
A female wolf might also be a main character. She could be attracted to Draco's unique submissive nature, which is different from the more dominant male wolves in the pack. Their relationship could develop in an interesting way, with her helping Draco gain confidence while he in turn shows her a different way of looking at the pack's social structure.
Hermione could be one of the characters. She might initially be skeptical about Draco's situation but then be moved to help him out of a sense of justice or because she realizes the implications of a pregnant wizard being caged. Another character could be Harry Potter. He could be conflicted about helping Draco given their past history, but still feel compelled to do the right thing.
Hermione is often a popular character. She might be the one who discovers something unusual about the toys and helps Harry and Draco understand their significance. Ron could also be there, perhaps getting into some comical situations because of the toys. And sometimes, even the teachers like Dumbledore or Snape can make an appearance, maybe guiding Harry and Draco in their toy - related adventures.
Narcissa Malfoy could also be important. As Draco's mother, she might have mixed feelings about the situation. On one hand, she wants to protect her son, but on the other, she might see the potential good in Harry and Draco working together for the baby's sake.
Ron Weasley often makes an appearance. He might be suspicious of Draco's intentions towards Hermione and try to protect her. His loyalty to Hermione and his hot - tempered nature can add a lot of drama to the story.
Well, Draco Malfoy himself would obviously be a major character. He'd be guiding or sometimes over - protecting his daughter. Harry Potter could also be a character. Maybe he's now a teacher at Hogwarts and has an interesting relationship with Draco's daughter, like being a mentor of sorts. Hermione Granger, if she's also on the faculty, could be another important figure, perhaps teaching the girl some valuable lessons about magic and acceptance.
It could be Hermione. Given her strong - willed nature and her often - clashing relationship with Draco, she might be the one to put him in such a situation. Maybe she discovers a new spell or magic item that allows her to do this as a way to keep Draco in line during a particularly tense time at Hogwarts, like when there are threats from dark forces and she doesn't trust Draco not to side with the wrong people.
The plot could involve a character who discovers Draco, a mysterious and powerful creature, and decides to keep it on a leash for safety reasons. But Draco doesn't like being restrained and tries to break free. This leads to a series of adventures as the character tries to keep Draco under control while also uncovering the secrets of Draco's origin.