Trigger Warning: Depictions of suicide.
Mugen Train follows the main cast of Tanjiro, his sister Nezuko (who has turned into a demon, but is docile), Zenitsu, and Inosuke, as they join the Flame Hashira (one of the most powerful Demon Slayers) Kyojuro Rengoku on the Mugen train to investigate and hopefully stop demon attacks that leave people missing. Despite following mainly Tanjiro, this film is about Rengoku. If you had seen the series beforehand, which is definitely recommended, you actually do not know that much about Rengoku, and his character is explored in the film. Also if you have not seen the series and go into the film blind, the first 15 minutes of the film give audiences a pretty clear view of each major character as well as the world they live in, and is done in a way not to make the viewer who has done their homework bored. As the film progresses you do get to learn deeper aspects of characters.
A lot of emotion comes out in Tanjiro’s actual dream sequence, where he gets to be reunited with his family, who all had died at the beginning of the series. While this is another great way to fill in first time viewers of the main character’s past, it also serves as a great character moment as Tanjiro starts to come to his senses. The internal struggle he faces when he eventually realizes he is in a dream and has to leave his family behind again is a highlight of the film. Another interesting and particularly heavy note, which also highlights Tanjiro’s character is the way to forcefully exit the dream, which is to die or essentially commit suicide. Tanjiro slices his neck to get out, and then does it more than once as he has to fight Enmu, the demon that put everyone to sleep. He does it so many times that he has to be saved from accidentally doing it in the real world. Even Enmu admits that it takes incredible mental fortitude and says that Tanjiro is “out of his mind.” Despite what it may look like to some, I do not think that it glorifies suicide and instead does the opposite. To make someone have to kill themselves in order to leave the dream is cruel and incredibly hard, which is why Enmu looks so surprised and exemplifies how motivated Tanjiro can be.