Well, perhaps the story could start with Stiles facing some great danger that forces him to undergo a transformation into an alpha. He might have to battle some powerful enemies and in the process, learn to control his new alpha powers. It could also involve his relationships with other characters changing as he takes on this new role.
There could be a group of hunters who see Stiles as a new threat now that he is an alpha. They might think he will be more dangerous and unpredictable, so they target him. Also, some supernatural creatures that have a vendetta against alphas in general could oppose Stiles.
One idea could be that Stiles is turned into a vampire against his will. Maybe he's attacked one night while out investigating something supernatural. As a vampire, he has to struggle with his new urges, like the thirst for blood, while still trying to be the same person his friends know. He might start to see the world in a different light, both literally and metaphorically, as his vampire senses heighten.
Scott would be the most likely one. He's Stiles' best friend and the True Alpha. He would never let the Alpha pack harm Stiles and would go to great lengths to rescue him.
Well, it could be about Stiles having a special connection to Peter as his alpha. Maybe it involves Stiles getting mentored by Peter, learning about the ways of being a werewolf under his guidance. They might go on adventures together, facing other supernatural threats in the town.
One great Stiles x Alpha Peter fanfiction is 'The Bond'. It delves deep into their relationship, exploring how Stiles, with his intelligence, and Peter, with his alpha power, come together. Another one could be 'Fated Encounter' which has an interesting plot where they meet in a rather unexpected situation. And 'Unlikely Allies' shows their journey from being at odds to falling in love.
The theme of transformation is also prevalent. Stiles may undergo some sort of personal transformation under Peter's influence as alpha. This could be emotional, like becoming more confident, or it could be related to some sort of supernatural ability. It adds depth to the relationship between them and makes for an interesting read.
Well, it's because it gives a new perspective. Stiles is usually seen in a different light in the show, and making her an alpha female flips the script. It's exciting to see her in a powerful role.
Power and responsibility is a major theme. Stiles has to learn to use his alpha power wisely while being a human. He can't rely on the natural instincts that other non - human alphas might have. Also, the theme of acceptance is there. He has to be accepted by other supernatural beings in the story as a human alpha.
Well, aside from Stiles, Scott is bound to be a central character. Their friendship is so strong that Scott would immediately start looking for ways to rescue Stiles. Derek Hale is another likely character. Given his past with the alpha pack and his relationship with Scott and Stiles, he would have a role to play. Then there's Allison. Her family's history with the supernatural means she has skills and knowledge that could be useful in rescuing Stiles. She could be involved in the search and rescue operation, using her archery skills and knowledge of the supernatural world to help out.