Moments - 02 - Kimetsu no Yaiba The Movie, Mugen Train - (Kyojuro Rengoku)

From his introduction in the film we are shown that Kyojuro Rengoku is quite eccentric, or at the very least, different from anyone else. His appearance is distinctive, helping him stand out in a crowd, and this appearance matches his personality. From the moment the central characters meet him it is shown that he is incredibly passionate, and dedicated to his work. Regardless of what he himself believes, he will do what is right, and accept those that he deems worthy of being accepted. So much so that when he initially speaks to Tanjiro, it is quite distant and matter of fact, accepting Nezuko, who was herself a demon, not because he himself believes in her but because the head of the organization acknowledges her, and he accepts the head.

When we enter the dream state we see his past, training with his younger brother, and striving for the approval of his father, who was himself, once a demon slayer that walked away from his duties, yet remaining an inspiration for his children for what he once did. Despite Rengoku’s accomplishments his father sees no merit in them, though he is not disheartened, showing strength in one's own character and believing in the path that he has selected for himself. Not out of stubbornness, but because it is the path that he sees as the right one to take. Not once when he is interacting with his father, mother, or little brother, does he lie. He accepts things for what they are and chooses to move forward regardless through the strength of his conviction.

Once the dream has been broken, the first thing he does is to find the core characters who have since been spread throughout the train as a result of the demon that had taken over, not to take over from them, but to use this opportunity to teach them, to treat them as equals as opposed to children in need of protection. To entrust responsibilities so that they will learn and grow stronger. Strengthening the ranks of the demon slayers further. While the young slayers move forward, he fights to his utmost so that he can act as a safety net to make sure that even if they fail, no one would die. Composed in his instruction, strong in his demonstrations, and steadfast in his belief in the young slayers.

When a high-ranking demon arrives, he is the only one strong enough to protect not only the central characters, but the two hundred humans that were on the train. He does not hesitate in refusing to join the enemy ranks. Standing fast and fighting with everything that he had to protect the future generation of slayers that would carry on fighting and go on to protect people in the future. Being as strong as he is he understands the responsibility he holds in protecting those around him, refusing to take life for granted and choosing the easy way out. Instead he fights to the last on the path of the righteous.

Having met, taught, and protected the young slayers he accepts them all as strong and worthy successors moving forward, even Nezuko, because despite being a demon she displayed the qualities of a demon slayer and that in itself earns his respect. Rengoku lived by his ideals, treated others equally, protected those that were not strong enough to fight on their own, taught those who would fight the coming battles, and strove to be a man that would not choose the easy way out when things got hard. All these aspects coming together at the finale is what made his sacrifice so memorable.