Caroline Forbes could be a key character if there is a crossover with 'The Vampire Diaries'. Her growth from a high - school girl to a powerful vampire makes her an interesting addition. She could bring her own set of values and relationships into the 'the originals crossover fanfic' and have some really engaging interactions with the Mikaelson family, whether it's a romantic entanglement with Klaus or a friendship with Elijah.
Elijah Mikaelson is also a great choice. He is the more level - headed and noble of the Mikaelson siblings. In a crossover, he could be the diplomat or the voice of reason, interacting with characters who might be more impulsive or have different moral compasses. For example, if crossed with characters from 'Teen Wolf', he could offer a different perspective on the werewolf lore.
Klaus Mikaelson is definitely one of the most popular. His complex and often villainous nature in The Originals makes him a fascinating character to bring into the world of The Vampire Diaries. He can stir up all kinds of trouble and create new dynamics among the characters in Mystic Falls.
Percy Jackson himself is often a very popular crossover character. His unique powers and his heroic nature make him stand out. He can bring a different kind of energy to the world of The Originals. Another popular one could be Annabeth Chase. Her intelligence and strategic thinking can be a great asset in the complex world of The Originals where there are always power plays and battles to be won.
Amata is a popular choice. His unique powers and his role as a main character in Aquarion Evol make him a central figure for crossovers. He could interact with characters from other series in interesting ways, like sharing his piloting skills or learning new abilities from them.
Caroline Forbes can also be an interesting character in fanfiction. She has her own set of strengths and insecurities. In fanfiction, she can be put in different situations that test her loyalty, her love life, and her friendships. For example, she could be in a situation where she has to choose between her vampire friends and her human family in a more extreme way than in the show.
Definitely Damon Salvatore. He's the bad - boy vampire with a heart of gold (sometimes). In a crossover, he'd be a wild card. He has his own sense of justice and loyalty, but also a devil - may - care attitude. He could get into all sorts of trouble in the world of the Originals. His sarcastic remarks and his ability to charm his way out of (or into) situations would make for some great scenes. He might also form an unlikely friendship or rivalry with one of the Originals, like Kol perhaps. His backstory and his experiences in 'The Vampire Diaries' would contrast and collide in interesting ways with the Originals' world.
I think Caroline Forbes could be an interesting character to focus on. She's from 'The Vampire Diaries' which is related to 'The Originals'. If she were to be part of a 'The Originals' and 'Supernatural' crossover, she could bridge the gap between the two worlds. She's a strong - willed vampire who has learned to adapt and grow. Her positive attitude could contrast with the more brooding nature of some of the 'Supernatural' characters, and she could bring a fresh perspective to the team - up against whatever supernatural threat they face.
Yuki is a very popular character to focus on. She has a complex backstory, being raised among vampires and having a special connection to both the vampire and human worlds. Her relationship with Zero and Kaname also offers a lot of material for fanfic writers to explore, such as her inner conflict between her love for both of them and her duty to maintain the peace at Cross Academy.
Shikadai is quite popular. His laid - back yet intelligent nature makes for an interesting character to write about. Inojin and Cho - Cho are also good choices. You can focus on their growth as ninja, their relationships with their parents' generation, and how they contribute to the new ninja world in the 'naruto gaiden fanfic'.
Nagisa Shiota is also very popular. Fanfics could focus on his growth as an assassin and how his initially meek personality evolves over time. His unique skills and his friendship with other classmates can be great elements to build a story around.
Louise is a very popular character to focus on. She has a complex personality, being proud yet often insecure. Her growth as a mage throughout the series can be further explored in a fanfic, especially her relationship with her magic and how it evolves.