Rengoku is greatly enthusiastic in regard to his duties as the Flame Hashira, and often comes across as cheerfully eccentric. He is amiable, pure of heart, and boasts extraordinary technique and swordsmanship stemming from strict practice and discipline. He is an honorable warrior who adheres to his code of morals and principles; the most significant being his belief that those who were born strong have a duty to protect the weak. He always has a smile on his face and speaks loudly and boldly.