The plot might involve Grindelwald coming to Britain to recruit followers for his cause. Phosphene could be a symbol or a power source that he believes will help him achieve his goals. Tom Riddle, being a Slytherin and already showing signs of his dark nature, is approached by Grindelwald. However, Tom has his own plans. He wants to use Grindelwald's knowledge and Phosphene's power to rise to the top on his own terms. So, he plays a double - game, pretending to be a loyal follower while secretly plotting against Grindelwald.
A great plot could be centered around a prophecy in Britain that involves Grindelwald, Phosphene, and Tom Riddle. Grindelwald believes that by controlling Phosphene, he can change the prophecy to his advantage. Tom Riddle, on the other hand, has heard about the prophecy as well and wants to use it to his own benefit. Phosphene, which might be a sentient magical being, has its own will and doesn't want to be used by either of them. The fanfic could then follow the struggle between these three as they each try to manipulate the situation according to their own desires.
A fanfic like this might explore the dark magic that Grindelwald wields in the British wizarding world. Phosphene could be a new magical creature or a spell that has some connection to the events. Tom Riddle, being the cunning and ambitious young wizard, might see Grindelwald as a sort of role model, at least in terms of achieving great power. The story could show how the different magical elements and characters interact and how their fates are intertwined.
A really interesting take in a fanfiction could be that the Master of Death power in Harry gives him a new form of magic that is completely incomprehensible to Tom Riddle. Harry could use this to his advantage in their battles, always staying one step ahead. The story could also explore how this new power affects Harry's relationships with his friends, as they might be both in awe and a bit scared of his new abilities.
One possible plot twist could be that Tom Riddle kidnaps Harry not for the typical reasons like revenge or to gain power over the wizarding world. Maybe he discovers that Harry has some hidden knowledge about a long - lost magic that he wants for himself. Another twist could be that while kidnapped, Harry manages to find a way to get into Tom Riddle's mind and discovers his deepest fears, which he then uses to his advantage to try and escape. It could also be that there are other dark forces at play that Tom Riddle is actually trying to protect Harry from, in his own twisted way, by taking him away from the wizarding world for a while.
Perhaps in this fanfic, the apartment is a magical place that serves as a crossroads between different timelines. Tom Riddle stumbles into it while Hermione is already there studying some ancient magic. They are forced to co - exist in this small space. Tom is initially hostile, but Hermione uses her wits to keep him in check. As they interact more, they begin to understand each other's perspectives on magic, and a strange bond forms between them that could potentially change the course of the wizarding world.
A possible plot could be that Tom Riddle is forced to save Harry Potter as part of a magical pact or curse. He initially resents it but as he spends time with Harry, he starts to see the world through Harry's eyes. For example, Harry's kindness towards others, even those who are different or outcasts, could make Riddle question his own beliefs. The fanfic could then focus on how Riddle tries to balance his old dark desires with his new - found respect for Harry and the values Harry represents. There could be a lot of internal conflict within Riddle as he tries to decide whether to fully embrace this new path or return to his old ways.
Power is a frequently seen theme in tom riddle fanfic. Since Tom was always so obsessed with power in the original story, fanfics expand on this, showing how he might gain or lose power in different situations. Love is also a theme sometimes. It's interesting to see how love could potentially change Tom Riddle, as he was not really associated with it in the main series.
Well, one aspect to consider in a Tom Riddle and OC fanfic is the portrayal of Tom Riddle himself. If it's well - written, it can show his complex character, his path to becoming Voldemort. The OC in such a fic can add a new dimension. Maybe the OC is someone who tries to prevent his fall into the dark side. However, some fanfics might not do justice to the original lore and make Tom too soft or the OC too overpowered.
I really liked 'Hermione's Encounter with Tom'. It's a well - written fanfic that focuses on the psychological aspect of their relationship. Hermione is portrayed as trying to understand Tom's motives and the reasons behind his actions. It shows her using her knowledge from Hogwarts to try and figure him out. It's a great read if you like exploring the characters' minds.
One great Tom Riddle and Hermione Granger fanfic is 'A Different Time'. It imagines what would happen if Hermione traveled back in time and encountered Tom Riddle before he fully turned into Voldemort. The story is full of interesting character interactions and Hermione's attempts to prevent Tom from going down the dark path.
In this type of fanfic, a really interesting plot might be that Harry and Tom Riddle are in an alternate reality. In this reality, Hogwarts has a different set of rules and magic. They are both outsiders in this new world. They start to rely on each other for survival, and in the process, they discover new aspects of their magic and themselves. Harry tries to use this opportunity to redeem Tom Riddle, while Tom is constantly tempted by his old, dark ways.