Dumbledore could play a role. Even if he's not physically present, his influence could be felt. Maybe Harry remembers Dumbledore's teachings while in timeout and gets some inspiration from them. Also, some of the Death Eaters like Bellatrix could be involved as they might be guarding Harry during his timeout.
Neville could be a significant character. He might step up in Harry's absence and start planning a counter - attack against Voldemort. And Luna could be there too, providing some unique insights and ideas to the group that's trying to free Harry from the timeout.
Hermione could be a main character. She might be trying to find a way to rescue Harry from the timeout situation. Ron could also be there, supporting Hermione in her efforts.
In this fanfic, perhaps Voldemort has some grand plan. He puts Harry in timeout to wait for the right moment. He might be using this time to gather his Death Eaters and prepare for a big showdown. Harry, while in timeout, could be thinking of ways to break free and defeat Voldemort once and for all.
Snape could also be a character in such a fanfic. His complex relationship with both Harry and Voldemort makes him an interesting addition. He might be in a difficult position, having to keep his cover as a double - agent while also trying to find a way to save Harry without revealing his true intentions to Voldemort.
Snape could play a crucial role. Given his past with both Voldemort and his role at Hogwarts, he might be torn between his loyalty to Dumbledore's cause and his complex relationship with Harry. He could be the one who has to make a difficult decision when Harry starts to side with Voldemort. Additionally, Draco Malfoy could be involved. He might see Harry's change as an opportunity to gain more power within Voldemort's ranks, or he could be jealous of Harry's new - found position with the Dark Lord.
The Weasley family in general would be involved. Ginny, for instance, would be heartbroken seeing Harry on Voldemort's side. The family's loyalty to Harry would be put to the test, and they would be among the main characters as they try to either bring Harry back or fight against him if he goes too far with Voldemort.
Hermione is often a very popular character. She can bring her intelligence and magic skills to help Harry in new and interesting ways in the fanfiction world. For instance, she might come up with a unique spell to counter Voldemort's dark magic.
In many of these fanfictions, the Marauders (James, Sirius, Remus, and Peter) are quite popular. They were friends of Harry's parents and their presence in a time - travel story can bring a sense of nostalgia and also add a lot of action and adventure. Bellatrix Lestrange can also be a prominent character on Voldemort's side. Her fanatical loyalty to Voldemort and her dark magic skills can make for some intense and exciting scenes, especially when she clashes with the heroes in different time periods.
Hermione is often a popular character. She might play a role in helping Harry understand the implications of Voldemort's reincarnation, using her vast knowledge of magic and history.
It could be Dumbledore from beyond the grave. He might find a way to reach out and summon Harry, believing that only Harry has the potential to truly defeat Voldemort in this new, dire situation.
Ron would also be important. His loyalty to Harry is unwavering. He might be the one who bravely volunteers to go on the most dangerous part of the rescue mission, perhaps facing off against some of Voldemort's most feared Death Eaters.
Hermione would be one of the main characters. She might be very skeptical at first about Harry's new friendship with Voldemort. She would constantly be on guard and try to figure out Voldemort's true intentions. Another would be Dumbledore. He would likely be watching the situation closely, trying to guide Harry and also be prepared to deal with Voldemort if he reverts to his evil ways.