In some fanfictions, they might rewrite the possession scene completely. Instead of the typical way it was shown in the books, they could add new magical elements. Maybe Quirrell has some hidden magic that reacts to the possession, creating a more complex and engaging story.
A really unique part of these fanfics is how they can change our perception of Quirrell. Instead of just seeing him as a simple villain, they can show his inner turmoil. Some fanfics might depict him as a victim of certain circumstances or having a more complex moral compass. Also, the relationships he forms in fanfics can be different from what we expect. He might have unexpected friendships or alliances that add new layers to the story.
A common theme is the battle for control. Harry is constantly fighting against the possessing entity for control over his body and mind. For example, in many fanfictions, he tries to resist using dark magic that the entity might force him to do.
One great 'Harry Potter Quirrell fanfic' is 'The True Nature of Quirrell'. It delves deep into his character, exploring his motives beyond what we see in the original books. Another one could be 'Quirrell's Hidden Past' which uncovers secrets about his life before Hogwarts. There's also 'Quirrell's Redemption' that offers an interesting take on if he could have been redeemed.
Perhaps Harry is tricked. Quirrell could be using some sort of mind - influencing magic or deception. He might make Harry believe that giving him the stone is the only way to save his friends or Hogwarts. Harry, being young and inexperienced, might fall for such a ruse and hand over the stone without fully realizing the consequences.
One possible consequence could be that Voldemort, who is using Quirrell, gains more power. Since the Philosopher's Stone has the ability to create the Elixir of Life, Voldemort could use it to create a new body or regain his full strength much faster. This would put Hogwarts and the entire wizarding world in great danger as Voldemort is extremely powerful and evil. He would likely start to hunt down those who oppose him, especially Harry Potter, with even more vigor.
Dumbledore could be the key character. He's extremely powerful and knowledgeable. He might sense that something is wrong with Harry and use his vast magical abilities and wisdom to find a way to exorcise the demon. He could also call on the help of other powerful wizards or even use some ancient magic artifacts to save Harry.
A great one is 'Quirrell's Hidden Struggle'. In this fanfic, it really shows how Quirrell's personality changes as he gets possessed. You can see the transformation from a timid professor to a more menacing figure under Voldemort's influence. It's interesting to see how the author plays with his character development.
In this fanfiction, a really engaging plot development could be the discovery of a hidden connection between the demon and Harry's past. Maybe the demon was once summoned by one of Harry's ancestors and now it's seeking revenge on the Potter family through Harry. As a result, Harry has to not only fight the possession but also uncover the secrets of his family's history to break free from the demon's hold.
Well, Harry could marry one of the veelas. Given their beauty and allure, it would add an interesting dynamic to the story. Their relationship could involve Harry having to deal with the jealousy of other wizards and also the cultural differences of the veelas. Or he could marry a descendant of one of the founders of Hogwarts. This would tie in a lot of Hogwarts history into their relationship, and their wedding could be a grand event that unites different factions within the wizarding community who have ties to the founders.