ron got a howler

It could be a really intense and unexpected turn. Maybe it would be full of threats and taunts from Voldemort to mess with Harry's mind.

Well, if Harry got a howler from Voldemort, it might be filled with dark magic and menacing words to unnerve Harry. It could also be a ploy to throw him off his guard and disrupt his focus on fighting evil.

His mother could send the howler. In the wizarding world, mothers can be quite fierce when it comes to family reputation and she might be unhappy with Sirius's actions or friends.

One big challenge is their own immaturity. They are still young and might not be fully ready to be parents. Emotionally, they'll have to deal with the stress of a new relationship dynamic. Financially, as I said, it's a huge issue. They'll need to figure out housing too. And education for the child in the future is another thing to worry about. They'll also have to face the possible judgment from their peers and the community at large.

It could be Severus Snape. He has a complex relationship with Dumbledore. Maybe Snape discovers some of Dumbledore's plans that he doesn't agree with regarding Harry Potter. He then sends a Howler in a fit of anger to express his disapproval.

Perhaps another student, like Hermione, could send the Howler in a very creative twist in the fanfiction. Maybe she has found out that Draco is planning something malicious against the Gryffindors and uses the Howler as a way to threaten him into stopping.

Hermione could be the sender. If Snape has made some unfair judgment in class against Gryffindor students, Hermione, with her strong sense of justice, might send a howler to him to voice her protest.

His mother is a likely sender. She could be worried about Remus and send a Howler to remind him to take his Wolfsbane Potion regularly or to be more cautious around others. Mothers are often protective, and in the wizarding world, a Howler is a rather forceful way to get your point across.

It could be Professor Snape. He often had a contentious relationship with Harry, and if Harry did something that Snape thought was particularly wrong or against school rules in a way that affected Snape's interests, he might send a Howler.

It could be Dumbledore. He was always one to oppose Voldemort and a howler from him would be a very interesting plot point. He might use it to taunt Voldemort or to try and make him second - guess his actions.