Definitely Percy and Dean. Percy has his quick - thinking and his water powers from being a son of Poseidon, while Dean is the tough, street - smart hunter. Their different personalities and skills would create an interesting dynamic. They could learn from each other, like Percy teaching Dean about Greek mythology and Dean showing Percy some of his hunting tricks.
Grover and Castiel would be an unexpected but interesting pair. Grover is the satyr who is all about nature and protecting it. Castiel is the angel who is a bit clueless about human ways. Grover could introduce Castiel to the beauty and importance of nature in a more hands - on way, and Castiel could use his angelic powers to help Grover in some of his more dangerous missions.
I think Annabeth and Sam would be a great pair. Annabeth is highly intelligent and strategic, and Sam is well - read and also very smart. They could work together to solve the mysteries that come up in the crossover. Sam could help Annabeth understand some of the more modern, non - Greek - mythology - related things, and Annabeth could use her strategic mind to help Sam in his research.
Percy Jackson and Mal would be an interesting pair. Percy has his water powers and his heroic, yet sometimes impulsive nature. Mal has her magic and her complex background as a VK. They could learn a lot from each other. Percy could show Mal that not all heroes are born into perfect situations, and Mal could introduce Percy to the different kinds of magic in the Descendants world.
Grover and Sam would be a fun combination. Grover is kind of goofy and has his own unique charm, and Sam is tough and not easily intimidated. They could get into all sorts of comical situations together, like when they go on a hunt for a mythical creature that has escaped into the city where iCarly is set.
Jason Grace and MG would also be an exciting pairing. Jason has his abilities as a son of Jupiter, his control over lightning and his Roman military training. MG is a vampire in Legacies. They could form an unlikely alliance. Jason could teach MG about discipline and honor from the Roman point of view, while MG could show Jason the unique aspects of being a vampire, like enhanced senses and the ability to move quickly. They could team up to protect their friends from threats that target both the demigod and vampire communities.
Ron and Grover would be a fun combination. Ron is a bit of a foodie and has a great sense of humor, while Grover is a satyr who loves nature and is always a bit nervous. They could get into all sorts of comical situations together, like when they accidentally set off a magical trap in Hogwarts while looking for food in the kitchens, or when they try to communicate with the magical creatures in the Forbidden Forest and end up scaring each other.
I think Annabeth and Black Widow would be an interesting pair. Both are strong, intelligent women. Annabeth's strategic mind from her demigod training could work well with Black Widow's spy skills. They could be on a mission to infiltrate a secret lair that has something to do with both the Greek and Marvel worlds.
Hermione Granger and Annabeth Chase would be an amazing pair. Hermione is super - intelligent, book - smart, and loves to study magic. Annabeth is a strategist, with a vast knowledge of Greek mythology. They could share their knowledge, Hermione teaching Annabeth about wizarding spells and Annabeth introducing Hermione to the lore of the Greek gods. They could also work together to solve complex problems that require both magical knowledge and knowledge of mythology.
Arya Stark and Castiel. Arya is a skilled assassin with a thirst for revenge. Castiel is an angel who often struggles with understanding human emotions. Their interactions could be really fascinating. Castiel could help Arya understand the deeper spiritual side of her revenge, while Arya could teach Castiel about the importance of personal vendettas in the context of the cut - throat world of Westeros.
Castiel and Danny would be an unexpected but cool pairing. Castiel is an angel with his own unique powers and view of the world. Danny's half - ghost nature would be something completely new to Castiel. They could have some really deep and strange conversations about the nature of life, death, and the afterlife. And when it comes to fighting enemies, their combined powers could be really effective.
Iron Man and Castiel would be an interesting pair. Iron Man with his high - tech gadgets and Castiel with his angelic powers. Iron Man could be intrigued by Castiel's ability to teleport and heal, and Castiel might be fascinated by Tony's technology. They could work together to fight a threat that combines technology and the supernatural, like a group of demons that are using stolen Stark tech.
Definitely Dean Winchester and Barry Allen. Dean has his tough - as - nails hunter attitude and Barry is the optimistic speedster. They could have some great banter while on a mission together. For instance, Dean might be constantly amazed at Barry's speed but also make fun of how he doesn't know how to handle a real weapon like a gun.