Then there's Finn. He's the hero in Adventure Time and when he enters the world of Harry Potter, fans love to see how his sense of adventure and his strong moral code play out. He might not understand all the wizarding customs at first, but his determination to do the right thing would surely make him stand out. Also, Ron Weasley could have some really funny moments when paired with the Adventure Time characters due to his sometimes clumsy and humorous nature.
Hermione Granger is also a common favorite. Her intelligence and love for knowledge could lead to some really interesting storylines when she meets the characters from Adventure Time. She might be intrigued by the magical creatures in Adventure Time that are different from the ones she's used to in the wizarding world. And Princess Bubblegum from Adventure Time is quite popular too. Her scientific mind and leadership skills could make her a great ally or a formidable opponent in the Hogwarts setting.
In these crossovers, Harry Potter himself is often very popular. People like to see how he'd react to the strange and wacky world of Adventure Time. Another popular character is Jake. His stretchy powers and laid -back attitude make for interesting interactions with the more serious Harry Potter characters.