The other demigods from Camp Half - Blood should be included. People like Clarisse, who at first might seem grumpy about the whole wedding thing but then has a change of heart and gives a really nice gift. And Nico, who could use his powers to create some amazing lighting effects during the evening reception. Their presence would add a lot of flavor to the story.
A fanfic could focus on the wedding preparations. Annabeth is in charge of most of it, with Percy trying his best to help. There are comical moments like Percy accidentally setting the tablecloth on fire while trying to light the candles for the rehearsal dinner. And then on the wedding day, everything goes perfectly, with a beautiful sunset as they say 'I do'.
Grover would be a great addition. In an AU, he could be Percy's best friend who is always getting him into (and out of) trouble. For example, in a college AU, Grover could be the one who convinces Percy to join a wild fraternity. He could also provide some comic relief. Another good character is Thalia. In a superhero AU, she could be a powerful superheroine with lightning powers. She could be a mentor or a rival to Percy and Annabeth, depending on the plot.
Grover would be a great addition. He could be the quirky sidekick in the high school setting, always getting into comical situations while also providing some sage advice to Annabeth and Percy based on his own experiences. For example, he could help Percy figure out how to ask Annabeth to the prom.
Grover could be a great addition. He could be the goofy but loyal friend who always gets caught in the middle of Percy and Annabeth's drama. For example, he might accidentally spill some secrets that cause more trouble between them. Another good character could be Clarisse. She could be the school bully who has a grudging respect for Percy and Annabeth but still tries to cause problems for them now and then.
Grover could be a great addition. He's Percy's best friend, and his presence can add some comical relief to the story. For example, he could accidentally interrupt a romantic moment between Percy and Annabeth, leading to some awkward but funny situations.
Obviously, Brock should be included. He has been Ash's friend for a long time and could be Ash's best man. He would also add some comical moments to the story, like when he flirts with the female guests at the wedding. Max, May's little brother, would also be a great addition. He could be a bit of a troublemaker at first, not fully understanding why his sister is getting married, but then come around and be really happy for her. And of course, all of Ash's Pokémon, like Pikachu, should be there. Pikachu could even be the ring - bearer in a really cute way.
Definitely Grover. He could be like their go - to babysitter when they want some alone time. He'd tell their child all kinds of stories about the old days. Another great character would be Tyson. He might build them a really cool house by the sea as a wedding gift, and he'd visit often to show them his latest inventions.
Mentor - like characters can also be great in a Percy Piper fanfic. They can guide Percy, pass on wisdom, and help him grow as a character. Maybe an old wizard who has been around for ages and has a lot of knowledge about the magical world.
Obviously, Grover has to be there. He's Percy's best friend. He could be the one who gives a really heartfelt speech at the wedding. Also, Chiron would be great. He could offer some wise words to the newlyweds. And Tyson, Percy's half - brother, would add a fun element with his big, kind heart.
Definitely Toad. Toad has been a loyal friend to both Mario and Peach. He could be the one helping with all the little details of the wedding, like arranging the flowers or setting up the chairs. Yoshi could also be a great addition. He could carry Mario and Peach on their honeymoon as a fun way of transportation. Luigi should be there too, as Mario's brother, he would be an important part of the celebration.