Celina
As she has been trained largely in Duel Monsters and confined in Academia's castle since her childhood, Serena is serious-minded, but has no social skills as a result, not seeing what was wrong with changing her clothes in front of Tsukikage and not understanding that not everyone is a Duelist. When first introduced, she is constantly trying to prove herself worthy to Leo Akaba and wants to fight Academia's enemies, and even members of Academia when necessary. She's strong-willed and determined to prove that she is strong and is willing to put herself in danger to prove this. Ironically, while wanting respect, she is very rude to others, believing herself superior to them. Also, in her desire to earn respect and the right to move about freely, she is shown amoral in her actions. She is willing to randomly attack any and all Duelists who use Xyz Monsters, even innocent bystanders in the same manner Shun would randomly attack any LDS students and teachers prior to cooperating with the latter, simply to prove her self-worth with no regard in how her actions affect others.