Caroline Forbes would be an excellent ally. She's strong - willed and has a good heart. She could help Rebekah's son navigate the social aspects of the vampire world, like how to handle vampire politics. Also, her friendship with the Mikaelsons could make her a natural protector for Rebekah's son.
Bonnie Bennett would be a powerful ally. Given her witch powers, she could help Rebekah's son understand any magical elements that might be related to his own powers. She could also use her magic to protect him from dark spells or curses that might be cast upon him by their enemies.
The plot might involve Harry trying to hide his true identity as a Mikaelson. He could struggle with the fact that he's different from other wizards. His relationship with his friends, like Hermione and Ron, could be strained as he tries to keep this secret. Also, the Mikaelson family might try to get him involved in their vampire world affairs, which would create a whole new set of challenges for Harry.
One idea could be that Rebekah's son discovers a hidden power within him that links to the family's dark past. He might struggle to control it while also trying to fit into the human world. For example, he could accidentally use this power during a school event, causing chaos.
In the fanfiction, some minor gods or goddesses related to love and beauty could be good allies for Percy. They might not be as well - known as Venus, but they could offer unique skills or knowledge. For example, the goddess of charm could teach Percy how to use his charm in a more strategic way, which would be very useful when he's trying to persuade someone or get out of a tight spot as a Son of Venus.
Annabeth would definitely be a great ally. Her strategic mind could help Percy navigate the complex situations that come with his Titan heritage. She could also research about Titans and find ways to counter any threats that target Percy because of his parentage.
He would probably be more confident. Since the Mikaelsons are known for their assertiveness, Harry might inherit some of that trait. He could be more bold in standing up to his enemies, not just Voldemort but also bullies at Hogwarts.
His mother Tsunade could be one of his first and most important allies. She would surely use her influence and skills to protect and guide him. Shizune could also be an ally, as she has been with Tsunade for a long time and would likely support the OC. Additionally, Naruto could be an ally, as he is known for befriending and helping out those in need in the ninja world.
Nico di Angelo would be a great ally. Since Nico has his own connection to the Underworld and the darker aspects of the demigod world, he and Percy as the 'Son of Night' could work well together. They could share knowledge about shadow - related powers and underworldly secrets.
Klaus could be a great supporting character. He has a complex relationship with Rebekah, and his overprotective nature towards his family could extend to the baby. He might be a bit of a wild card, sometimes causing trouble but also being a powerful ally. Elijah is another good option. He's the more level - headed of the Mikaelson siblings, and his wisdom could be valuable in guiding Rebekah in raising the baby. Also, Hayley could be involved. Since she has her own experiences with having a baby in the supernatural world, she could offer practical advice and support to Rebekah.
Aang could be an ally. Despite the OC being Ozai's son, Aang, with his forgiving nature, might see the potential for good in the OC. He could help the OC to understand the importance of balance and peace.
One great Rebekah Mikaelson fanfiction is 'Rebekah's Redemption'. It delves into her complex character, showing her growth and struggles in a new light. The story is well - written, with vivid descriptions that really bring the 'Vampire Diaries' world to life.