Ryu Yamada is a fictional character from the Japanese manga and anime series titled Yamada-kun and the Seven Witches. He is a high school student known for his delinquent appearance and laid-back attitude. Ryu's life changes dramatically when he discovers he has the ability to switch bodies with others through a kiss. In the story, Ryu becomes involved with a group of students who possess unique powers, known as the Seven Witches. His character development explores themes of friendship, identity, and the challenges of adolescence, making him a relatable figure for many readers and viewers.