How Did Rengoku’s Death Happen? Killing the Flame [Spoilers]

Demon Slayer is one of the most popular anime series of all time. Its movie, Demon Slayer: Mugen Train, sold 41 million tickets and made over $504 million globally. 

The film also contains many essential details about Demon Slayer; the most important of which is how Kyojuro Rengoku’s death happened. We will uncover this in this blog.

Is Rengoku Kyojuro Really Dead in Demon Slayer Mugen Train?

Yes, Kyojuro Rengoku is dead in the Mugen Train Arc.

Who Caused Rengoku’s Death?

Who Caused Rengoku's Death?

He died in the battle with an upper moon, Akaza.

Akaza is the third strongest demon under Muzan Kibutsuji. He is a high-level demon. Through time, Akaza has found a way to get stronger. That’s why during their fight, he repeatedly tempts Rengoku to become a demon. That way, the two of them can fight for eternity.

Akaza used to be a talented fighter before turning into a demon. His life… sucked. Akaza’s childhood was full of pain. One day, he found a way to escape from that dark life, but the happiness did not last long. So, he went for revenge and was turned into a demon by Muzan after killing 64 people.

Why is Kyojuro Rengoku’s Death Important?

The death of Kyojuro Rengoku was inevitable when he fought with Akaza. 

However, his death was not meaningless. He saved 200 people on the Mugen Train, including an important character – one who would be necessary to kill Muzan later: Tanjiro Kamado. 

In fact, he died gloriously! After all, if Rengoku didn’t protect Tanjiro, the final descendant of Sun Breathing would disappear forever. Besides, Rengoku’s death ignited Tanjiro to make him unlock the Demon Slayer Mark. The mark of Tanjiro resonated with the other Hashiras and, in turn, helped them get their own marks.

This helps the Demon Slayer Corps so much to increase their power in the final battle with Muzan.

He died because of a stronger opponent.

The death of Rengoku had to happen so the story could keep running properly.

In the Demon Slayer universe, the rule is this: the weaker will lose the fight.

Akaza is a demon picked by Muzan who has lived for hundreds of years. The “killing achievement” of Akaza must be huge. With that said, Akaza is so strong to be stopped easily. 

If Rengoku fights with Akaza but manages to come back in one piece, everything the author built about Muzan’s army will be ruined. Of course, Rengoku’s death is sad, but we can’t change it because Akaza is stronger than him.

In case Rengoku could live after that fight, the story would change completely to another direction.

He died to slow down the growth of Tanjiro.

After the fight with Lower Moon-5 Rui, we all know that Tanjiro can use the Dance of Fire God, also known as Sun Breathing.

Sun Breathing is the origin of Breathing which was created by the strongest Demon Slayer – Yoriichi. Yoriichi used Sun Breathing and almost killed Muzan many centuries ago. To this day, we still see the scars his cut left on the body of Muzan.

Rengoku's death

If Tanjiro learned to use Sun Breathing too soon, the story would get boring. 

When the growth of Tanjiro is faster, it will reduce the charm of the series and eclipse other characters. All the Demon Slayers Corps just need to wait for Tanjiro to master the Sun Breathing and use Tanjiro as an ace in every battle with Muzan. 

If you take a look at another shounen anime/manga like Jujutsu Kaisen, a strong character like Gojo Satoru will block the development of the story. That’s why in the interview with Gege Akutami (the author of Jujutsu Kaisen), he revealed that the sealing of Gojo is necessary for the other characters to progress.

The same happens with Demon Slayer. If a character is too overpowering, the series will get stuck. Storywise, putting everything on the shoulders of a 15-year-old kid who just became a Demon Slayer recently will not be a wise choice.

Despite Rengoku dying in his youth, the legacy he left will be carved into others’ hearts. He lived a meaningful life, was admirable, and kept his chin up when he died. Life is short, and you only live one, so live by all of your heart to not regret anything.

2 Reasons Everyone Loves Rengoku

1. Kyojuro Rengoku’s Adversity

Everyone in the Demon Slayer Corps has unique circumstances, and Rengoku is no exception.

He belonged in a clan that had a tradition of killing demons through many generations. The Rengoku family birthed and raised many Demon Slayers in the Demon Slayer Corps. It also saved so many documents about demons.

Kyojuro Rengoku’s father, Shinjuro, was one of the strongest Flame Hashira in the series. He achieved a lot from killing demons. He was the one who passed the spirit and will to Kyojuro to become a Demon Slayer.

Rengoku family

But one day, that powerful Flame Hashira suddenly stopped with the Demon Slayer’s path. Instead, he started drinking all the time and blamed his sons for seemingly nothing.

It’s because Shinjuro read an old document about the origin of Breathing. He realized that all the Breathing right now is just the fake weaker version of Sun Breathing. And with the death of his wife, Ruka, his mind was completely destroyed.

He stopped training Kyojuro. In addition, he called his son talentless and had no potential to become a Demon Slayer. 

Well, in short, Kyojuro got psychological abuse when he was a child. If Kyojuro wasn’t strong and didn’t believe in himself, he probably gave up and did not become a powerful Hashira.

He trained himself.

Let’s imagine you grow a seed, but instead of providing water, fertilizing, and looking after it often, you trample and see it as a place to release anger. That seed rarely grows into a healthy tree. The same happened to Kyojuro. 

But he didn’t give up.

When his father stopped teaching him, Kyojuro trained by himself using the documents of the family. With his talent, he learned Flame Breathing and full focus breathing to become one of the strongest Hashiras in the Demon Slayer Corps.

Kyojuro Rengoku's childhood

The Breathing techniques are the most essential skills to help Demon Slayers increase their strength to fight demons. And full focus breathing is something only a person as strong as a Hashira level or near it could learn and use. 

The triad Tanjiro, Inosuke, and Zenitsu were trained hard under the guidance of other people to learn it. But with Kyojuro, he learned it by himself. That’s enough for us to know how talented he was and the effort he spent to become a Demon Slayer.

What an incredible guy!

And the reason he could firmly believe that is because of his mom. Her last words were the light to help Kyojuro overcome that hard time and focus on the purpose of his life.

2. Kyojuro Rengoku’s Personality 

The first time we see Rengoku is when he appears at the meeting with Hashira to talk about the case of Tanjiro and Nezuko.

At first, he and other Hashira didn’t agree with this case. How could a demon slayer stay with a Demon? But after seeing Nezuko can control herself not to attack humans and with the agreement of the Head of demon hunters, Kagaya, he didn’t say much about this case anymore. 

Rengoku's personality

Rengoku is an approachable and enthusiastic person. If someone asked him a question, he would answer it by 200% if he knew. His personality was special, and everyone loved him because of that.

All the Hashira agree that Kyojuro was a good guy. Even Tengen confirms that Rengoku is more flashy than himself, and asocial people like Giyuu, Sanemi, and Serpent Hashira also like his personality.

People who met Rengoku for the first time ,like Tanjiro, Zenitsu, and Inosuke, may find him as weird. But they would end up liking Rengoku later.

His sense of justice

One more outstanding thing about Rengoku is “justice.”

Kyojuro Rengoku hates demons so much. When he first learned about Tanjiro and Nezuko, Rengoku, despite respecting Kagaya, still protested against a Demon Slayer working with a demon. 

And during his final battle, Rengoku fought against turning into a demon, even if that meant death.

The Dream of Kyojuro Rengoku

The Blood Demon Art of Enmu uses the dream of opponents by touching their subconscious and trapping them in that space. 

When the group of Tanjiro, Zenitsu, Inosuke, and Rengoku are trapped in the Blood art of Enmu, they were all trapped into dreams. Tanjiro dreams of his family, the thing he lost forever. Zenitsu dreams of love with Nezuko. And Inosuke dreams of unreal things.

Rengoku's Dream

Unlike them, Rengoku didn’t dream of the happiest moment in his life when his mom was alive.

The dream of Rengoku couldn’t be more realistic. He dreamed of the first time he became a Hashira and announced it to his father. 

Rengoku’s spirit was so strong as to not let him dream of unreal things. Even in a dream, he still faced reality and the trouble of his life: the disparagement and estrangement from his father. 

With that said, an unhappy childhood and an extraordinary personality built Kyojuro Rengoku – Flame Hashira of the Demon Slayer Corps. And those are the things that make other people love him. 

Rengoku’s Death: the Final Battle of a Great Flame Hashira

Kyojuro Rengoku was truly an embodiment of a Flame. His look, his personality, it all related him to a flame. 

Rengoku was one of the strongest of the Demon Slayer Corps. He mastered swordsmanship, and the power, speed, and understanding of nine forms of Flame Breathing were proof of it.

And Rengoku showed all of it in the final battle with Akaza. Even one of the strongest demons admired the power of Kyujuro. 

Rengoku's death

Every time he got cut by Rengoku, Akaza shook with interest. Akaza always called his name like they were friends for hundreds of years.

He invited Rengoku to become a demon throughout the fight. If that happened, they can fight again. However, Rengoku wanted to die naturally. He wanted the death of the old. That’s the beauty of life that Rengoku wanted.

The fight between Akaza and Rengoku was so breathtaking that Inosuke and Tanjiro can’t do a thing but only look from the outside. 

But now, Rengoku had to fight with one of the strongest demons. Even when Rengoku got injured badly, he still held his blade tightly and cast the strongest form of Flame Breathing, Ninth Form: Purgatory.

GIF of Akaza and Kyojuro exchanging blows

It was so strong and cut Akaza with many slices. However, it was not enough. Akaza had enough time to punch Rengoku through his body. And Akaza’s ability to regenerate was too overpowering. He fixed his body immediately after that. 

At that moment, Kyojuro remembered his mother and used all the power left to chop one hit to the neck of Akaza. He also stopped a punch directly to his face with unbelievable strength. 

The emotion of Akaza changed from excitement and enjoyment to fear and started to speed things up because dawn was coming. 

He tried to escape from Rengoku, but couldn’t because the Flame Hashira was holding his arms tightly. So, he escaped by giving up those arms while the blade of Rengoku was still against his neck. 

rengoku death

Kyojuro died with a smile after remembering his mom. He finished his duty well.

The death of Kyojuro Rengoku spread to other Pillars and all of the Demon Slayers.

This is also the end of the Mugen Train movie.