When Leonidas first appears, he is a Bakugan with a large hunger for battle and stayed away from other Bakugan. All of this had changed when he battled alongside Valentin. He grew protective of Valentin and became close friends with him. He also lost his large hunger for battle and gained a sense of justice in return. He gets along well with other Bakugan, but is usually quiet and serious. However, Leonidas sometimes helps play pranks on Valentin, and like Valentin, is against people doing things against their will. He works well with other Bakugan and other Brawlers as well as when working with Valentin in brawls and outside of brawls.