Manabu Saien, who is called Kyuju or Professor by his friends and teammates, is the technical and intellectual backbone of the Blade Breakers during the events of Beyblade the Movie: Fierce Battle. In this standalone film set after the second season, he accompanies his teacher and the rest of the team on what begins as a leisure trip. Saien is a young, highly intelligent boy with a passion for all things mechanical and scientific, constantly analyzing and upgrading Beyblades to give his team a competitive edge. His personality is calm, methodical, and somewhat reserved; he often acts as the voice of reason among the more impulsive Bladers. His primary motivation is the success and safety of his friends, applying his knowledge to solve technical problems and understand the mysteries they face. In the movie, his role shifts from that of a mere supporter to a key strategist when the team confronts the ancient dark bit beasts that possess four children. Saien uses his analytical mind to help decipher the nature of the dark energies and assists in counteracting the threats. His bond with Tyson Granger is close—he respects Tyson’s passion and often provides crucial advice. He also shares a friendly camaraderie with Max, Ray, and Hilary. While Saien seldom engages in direct Beyblade battles himself, he demonstrates resourcefulness and courage when the team is in danger. His notable abilities include deep technical expertise in Beyblade mechanics and the capacity to remain composed under pressure, making him an indispensable asset in the fight against the Shadow Bladers. Throughout the film, his quiet dedication highlights the value of intelligence and teamwork over sheer fighting strength.