Optimistic, Cheerful, Willing to prove himself, Simple, Respectful of elders, Helpful, Kind. Upbeat, Outgoing, Proud of being a jujutsu sorcerer, Age: 17 years old. Yu Haibara from Jujutsu Kaisen is a cheerful and optimistic young man. He's a first-year sorcerer who's courageous, enthusiastic, and kindPersonality. Yu was an optimistic and cheerful young man who was willing to prove himself to his upperclassmen.