[Reading Demon Slayer Through Buddhist Mythology] The "Twelve Kizuki" and Buddhism: What is the Hidden Meaning of "Upper Rank" and "Lower Rank"?

Hey everyone, it’s Osamu!

Demon Slayer is just incredible, isn’t it? The battles, the characters... but what I find really fascinating is the deep mythology woven into the story.

Today, I want to talk about the main antagonists: the Twelve Kizuki (十二鬼月).

We all know they’re the strongest demons directly under Muzan, but have you ever stopped to think about their names?

Why are they split into "Upper Rank" (上弦, Jōgen) and "Lower Rank" (下弦, Kagen)? This isn’t random. It has a deep connection to the Buddhist themes that run through the entire series.

Let's dig in!

What Do "Upper Rank" and "Lower Rank" Actually Mean?

First, let's look at the literal words.

• Jōgen (上弦), or "Upper Rank," is the Japanese word for the Waxing Moon (specifically, the first-quarter moon, when it's growing fuller).

• Kagen (下弦), or "Lower Rank," is the word for the Waning Moon (the third-quarter moon, when it's shrinking).

Both are names for specific phases of the lunar cycle. This is our first major clue.

In the world of Demon Slayer, demons (Oni) have one fatal weakness: the sun. Sunlight is the only thing that can truly destroy them. This means their entire existence is confined to the night.

The Moon (月, tsuki) is the absolute symbol of their world. It’s the light they live by.

Muzan Kibutsuji is the "king" of this night, and the Twelve Kizuki (which translates to "Twelve Demon Moons") are his most powerful servants, named after the very thing that rules their dark world.

The Buddhist Meaning of the Waxing and Waning Moon

So, where does Buddhism come in?

In Buddhism, the moon is a huge symbol.

The Full Moon (満月, mangetsu) is often used to represent purity, awakening, or perfect enlightenment—the state of a Buddha.

Consequently, the phases of the moon—its waxing and waning—are a powerful metaphor for the cycle of Samsara (輪廻, rinne): the endless loop of birth, suffering, death, and rebirth that all beings are trapped in.

Now, look at the Twelve Kizuki again with this in mind:

• The Upper Ranks (Jōgen - Waxing Moon): This is the moon that is growing in power, moving towards the perfection of the full moon. This perfectly fits demons like Kokushibo, Doma, and Akaza. They are the most powerful, the most "complete" demons, and the closest to Muzan's twisted ideal.

• The Lower Ranks (Kagen - Waning Moon): This is the moon that is fading, decreasing, and moving towards the darkness of the new moon. This symbolizes their weakness, their incompleteness, and their disposability. Remember how easily Muzan dismantled them at the start of the arc? They are fading existences, easily extinguished.

Why the Number "Twelve"?

But why twelve? That number is also deeply significant in Buddhism.

You often see groups of twelve guardian deities, like the Twelve Heavenly Generals (十二神将, Jūni Shinshō), who serve and protect the Medicine Buddha (Yakushi Nyorai).

The Twelve Kizuki are a classic mythological trope: they are a dark inversion or a profane mockery of these 12 sacred guardians. Instead of protecting life, they serve Muzan, the progenitor of demons, and exist only to consume it.

Conclusion

When you look at it this way, Demon Slayer gets even deeper.

The names of the Twelve Kizuki aren't just cool-sounding ranks. They are a direct reflection of their power and their tragic, incomplete existence, all tied into the story's rich Buddhist worldview.

They are beings trapped in the "night" of Samsara, with the Upper Ranks getting closer to a "full moon" of demonic power, and the Lower Ranks fading into nothingness.

What other connections have you noticed in the series? Let me know in the comments!

This is Osamu, signing off.