One interesting plot twist could be that the Minotaur is actually a misunderstood creature under a curse. In some fanfictions, it might be revealed that he was once a heroic figure before being transformed. Another twist could be Percy having a secret power that he discovers while fighting the Minotaur that changes the whole dynamic of their encounter. For example, he might be able to communicate with the Minotaur's mind and find out its true motives.
One idea could be that Percy, after his encounter with the Minotaur, discovers a lemon tree in the Camp Half - Blood that has some magical properties related to the Minotaur. Maybe the lemons can be used to create a potion that can temporarily weaken the Minotaur's strength. Another plot could involve a lemon - themed quest where Percy has to retrieve a golden lemon that the Minotaur is guarding. It could be a symbol of power that the gods want to keep away from the monsters.
A cool plot could be a time - travel fanfiction. The Minotaur travels back in time to the era when the gods were more actively involved in the mortal world. He could interact with the gods, and Percy has to follow him through time to stop him from causing chaos. This would involve Percy having to deal with different rules and powers in the past, and also understanding the Minotaur's motives for going back in time.
A really cool plot twist might be that the reincarnated character realizes they are not just reincarnated into the Percy Jackson world randomly. They are part of a prophecy that was long forgotten. Their actions in this new life will either save or destroy the world of demigods. This would add a layer of high stakes and mystery to the fanfiction.
In some fanfictions, there could be a twist where the gods are not as all - powerful as they seem. Maybe they are being manipulated by a greater, unknown force. This would force Percy and his friends to re - evaluate their relationships with the gods and find new ways to deal with the threats to their world. It would also change Percy's destiny as he might have to take on a more independent role in saving the world without relying as much on the gods' help.
One interesting plot twist could be that the gods are actually players in this 'game' too. They manipulate events not just as deities but also as players with their own scores and goals. Another could be Percy finding out that his real power is not what he thought, like he has the ability to reset the 'game' world. And a third could be that some of the monsters are actually glitches in the game system, and Percy has to figure out how to deal with them in an unexpected way.
One possible plot twist could be that Percy discovers a hidden power within Tartarus that he can use to his advantage. Maybe it's a long - lost magic that only the darkest part of the Underworld can unlock.
One interesting plot twist could be that Percy discovers he has some of Achilles' more negative traits along with his powers. For example, Achilles was known for his pride, and Percy might start to struggle with excessive pride that gets in the way of his relationships with his friends at Camp Half - Blood. Another could be that the gods, fearing Percy's new connection to Achilles, send out a series of trials that are specifically designed to test his loyalty and his ability to control the power of Achilles. Maybe he has to face off against a powerful monster that can only be defeated if he uses his Achilles - like invulnerability in a very specific and dangerous way.
One interesting plot twist could be that Percy, instead of falling for the Aphrodite trap in the expected way, turns the tables and uses the situation to his advantage. Maybe he pretends to be under the spell to gather information from the enemies who set the trap.
Well, perhaps a plot twist is that Percy doesn't escape in the traditional sense. Instead, he finds a way to manipulate the rules of Tartarus so that he can exist in both Tartarus and the mortal world simultaneously. This could lead to some really interesting story developments as he tries to keep this a secret from his friends while also using his new - found ability to fight against the forces of evil. Also, it could be that the escape route he finds is actually a trap set by an enemy, but he manages to turn it around and use it to his advantage in a really unexpected way.
One interesting plot twist could be that a minor character from the original series turns out to be a powerful ally in the Battle of Manhattan in the fanfiction. For example, a seemingly harmless janitor at Camp Half - Blood who actually has the power to manipulate time and uses it to freeze the enemy forces at a crucial moment.