Kaiju No. 8 Manga: Complete Guide to the Monster-Hit Shonen Series

About Kaiju No. 8 (怪獣8号)

Kaiju No. 8 (怪獣8号), also known internationally as Monster #8, is a Japanese manga written and illustrated by Naoya Matsumoto. Serialized digitally on Shonen Jump+ since July 2020, the manga quickly rose to fame, becoming one of the platform’s most significant global hits.

Blending kaiju monster traditions (inspired by Godzilla and Ultraman) with modern shonen storytelling, Kaiju No. 8 delivers a thrilling mix of monster battles, heartfelt friendships, military action, and redemption.

With millions of copies in circulation and an anime adaptation produced by Production I.G (with Studio Khara collaborating on kaiju designs) scheduled for 2024, Kaiju No. 8 has solidified itself as a global phenomenon in the sci-fi shonen manga world.

Story Overview

At its core, Kaiju No. 8 explores the eternal theme of man vs. monster, but with a unique twist: the protagonist himself becomes the monster.

• Kafka Hibino, once part of a monster cleanup crew, dreams of joining the Japan Anti-Kaiju Defense Force alongside his childhood friend Mina Ashiro.
• During a kaiju attack, Kafka gets infected by a mysterious organism that transforms him into a powerful kaiju, labeled Kaiju No. 8.
• Despite his monstrous new form, Kafka retains his human mind and sense of duty. He uses his powers to protect humanity from kaiju threats, even while being hunted as an enemy.
• This creates a compelling underdog vs. prodigy dynamic: Mina is already a celebrated captain in the Defense Force’s 3rd Division, while Kafka struggles to prove himself.

The story develops across arcs like the Defense Force entrance exam, early battles against Honju Kaiju, the rise of Kaiju No. 9, and character growth for recruits like Reno Ichikawa and Kikoru Shinomiya.

Main Characters

Kafka Hibino (Kaiju No. 8)

The protagonist and titular Kaiju No. 8. Initially part of a kaiju cleanup crew, Kafka becomes a kaiju-human hybrid after infection. His journey represents redemption, second chances, and the struggle between man and monster.

Mina Ashiro

Captain of the Defense Force’s 3rd Division and Kafka’s childhood friend. She commands respect with tactical brilliance and calm leadership—symbolizing the prodigy archetype compared to Kafka’s underdog role.

Reno Ichikawa

A young recruit who looks up to Kafka as a mentor figure. Reno is a marksman with potential and represents the new generation of fighters stepping into the kaiju battlefield.

Kikoru Shinomiya

A child prodigy and the daughter of Defense Force commander Isao Shinomiya. Kikoru embodies the burden of legacy, balancing extraordinary talent with the pressure of family expectations.

Hoshina Soshiro

Vice-Captain of the 3rd Division and a close-combat specialist. Known for dual blades and a laid-back personality, he becomes one of Kafka’s most important allies.

Isao Shinomiya

Commander of the Defense Force and father of Kikoru. He is both an influential figure in the military and a key obstacle in Kafka’s journey due to his suspicion of Kaiju No. 8.

Kaiju and Antagonists

• Kaiju No. 9 – Main antagonist; a shapeshifting kaiju who infiltrates human society with long-term strategy.
• Honju Kaiju – Massive, catastrophic threats requiring the Defense Force’s full might.
• Yoju Kaiju – Smaller spawns/minions that appear during major attacks.
• Kaiju Weapons – Unique weapons derived from captured kaiju parts, letting humanity fight monsters with monster-born tech.
• Kaiju Classification System – A ranking method to measure threat levels and determine responses.

World-Building and Organizations

• Japan Anti-Kaiju Defense Force – Military organization that protects humanity.
• 3rd Division – Commanded by Mina Ashiro; central to many storylines.
• Recruitment Exams – Grueling tests where candidates prove their worth.
• Monster Cleanup Crews – Civilian teams that process kaiju remains; Kafka’s starting point.
• Kaiju Weaponization Technology – Humanity’s push to turn kaiju biology into powerful tools.

Themes and Symbolism

• Monster Transformation – Kafka’s dual identity blurs the line between man and monster.
• Responsibility and Duty – The Defense Force embodies sacrifice and military dedication.
• Friendship and Teamwork – Central shonen bonds among Kafka, Reno, Kikoru, and Mina.
• Redemption and Second Chances – It’s never too late to pursue a dream.
• Found Family Trope – The 3rd Division becomes a surrogate family.
• Prodigy vs. Underdog – Mina/Kikoru as natural talents; Kafka/Reno as grit and perseverance.

Key Arcs

• Kafka’s Transformation Arc – Kafka becomes Kaiju No. 8, fueling tension between duty and monstrous form.
• Defense Force Entrance Exam Arc – Kafka, Reno, and Kikoru undergo rigorous testing, setting rookie dynamics.
• Kaiju No. 9 Infiltration Arc – The shapeshifting antagonist escalates stakes as Kafka balances secrecy and protection.
• Kikoru Shinomiya’s Development – From proud prodigy to true teammate, strengthening the found-family theme.
• Third Division Battles – Under Mina, the unit faces massive attacks that push everyone to their limits.
• Military Weapon Upgrades – Kaiju-derived tech fuels an arms race against evolving monsters.

Media and Adaptations

The manga’s success led to a highly anticipated anime adaptation by Production I.G, with Studio Khara designing kaiju. The anime brings Kafka’s monster form and large-scale battles to life, riding the global monster-anime trend.

The series is often compared to Godzilla, Ultraman, and Pacific Rim, but stands out by centering a human protagonist turned kaiju.

Kaiju No. 8 – Frequently Asked Questions

Is Kaiju No. 8 still ongoing?

The manga ended on July 18, 2025 (chapter 129), while the anime is still ongoing with Season 2 airing weekly in 2025.

Who is Kaiju No. 9?

The series’ main antagonist: a highly intelligent, shape-shifting, parasitic kaiju that manipulates and revives other kaiju and infiltrates humans.

What makes Kafka Hibino unique as a protagonist?

He’s an adult everyman who can transform into a kaiju yet retains his human mind, balancing Defense Force duty with a secret monster identity.

Where can I read Kaiju No. 8?

Officially on VIZ Shonen Jump and Shueisha’s MANGA Plus (web or app), which host the licensed chapters.

When is the anime release date?

Season 1 premiered on April 13, 2024, and Season 2 premiered on July 19, 2025.

Where to watch Kaiju No. 8?

Crunchyroll streams the series (sub/dub); availability varies by region, so check your local catalog.

When is Kaiju No. 8 Season 2?

Season 2 began on July 19, 2025, with new episodes dropping weekly on Saturdays per the official schedule.

Is Kaiju No. 8 finished?

The manga is finished (chapter 129, July 18, 2025); the anime is not—Season 2 is currently airing.

Where to watch Kaiju No. 8 television show?

Crunchyroll carries the TV anime with simulcast and on-demand options, subject to regional licensing.

Is Kaiju No. 8 a hit or flop?

A clear hit—it set Jump+ growth records and surpassed tens of millions in circulation, with strong anime viewership.

What is the last chapter of Kaiju No. 8?

Chapter 129, published on July 18, 2025, concludes the manga’s story.

Who killed Kaiju No. 9?

Kafka Hibino (Kaiju No. 8), alongside the Defense Force, defeats No. 9 in the final arc, with Kafka delivering the decisive blow.

Is episode 12 of Kaiju No. 8 out?

Yes—Season 1, Episode 12 released on June 29, 2024, and is available to stream on Crunchyroll.

Conclusion

Kaiju No. 8 is more than just a monster manga—it’s a powerful story of second chances, friendship, and duty, wrapped in explosive kaiju battles and military drama. Naoya Matsumoto blends kaiju tradition with modern shonen storytelling to create a series that resonates globally.

If you’re looking for a manga that balances action, heart, and world-building, Kaiju No. 8 is a must-read. With the anime on the horizon and the manga’s momentum worldwide, now is the perfect time to join Kafka Hibino, Mina Ashiro, Reno Ichikawa, and Kikoru Shinomiya in their fight against monstrous threats.