Blade of the Immortal

Blade of the Immortal

Blade of the Immortal manga series cover art
Blade of the Immortal

Series Overview

Blade of the Immortal (Mugen no Juunin: Immortal / 無限の住人-IMMORTAL-) is an ONA series which began airing in the fall of 2019 and finished in the winter of 2020. If you’re wondering what an ONA is, it’s an original net animation, which just means it aired online rather than on TV.

But just because the O in ONA stands for original doesn’t mean this is an anime original series. Blade of the Immortal is based on a manga of the same name. And, although this doesn’t happen often, I enjoyed this anime so much I may actually read the manga.

For reference, the only other time I’ve read the manga after watching an anime was for Attack on Titan.

Rin Asano from the anime series Blade of the Immortal
Rin Asano

The best way I can describe Blade of the Immortal through comparison is to say it’s like a combination of Samurai Champloo and Dororo. It’s a classic tale of revenge involving ronin samurai, immortals, and a young girl who’s caught up in the middle of it all.

But before anyone tries to say that the inclusion of Rin, the young girl, in the series somehow makes it worse, allow me to enlighten you. Rin isn’t just some girl who has nothing to do with the events of the story. In fact, this is her tale of revenge.

After her parents are slaughtered before her eyes by a rogue group of samurai, Rin dedicates her life to seeking vengeance. However, because she’s not strong herself, she hires a swordsman to help her achieve her goal. This swordsman is Manji, an immortal man infamous for killing 100 men on his own.

The series follows this pair as they travel across Japan in search of the man responsible for killing Rin’s family.


The three main characters of the series are Rin, Manji, and Kagehisa. But there’s also a pretty large supporting cast of characters who are all extremely interesting in their own right. Unfortunately, it would take way too long to cover all of those characters, so I’ll breeze over them after the main trio.

Rin Asano is the protagonist of the series. She’s a 14-year-old girl and an only child. The reason her parents were killed is that her father was the master of a dojo and the antagonists of the series, the Ito-Ryu, killed him and other dojo leaders around the land to send a message to the shogunate.

While Rin herself isn’t really a swordswoman, that doesn’t mean she’s not skilled with weapons. She’s more of the assassin-type: opting to use needle-like kunai and poison to take out her opponents.

Manji from the anime series Blade of the Immortal

Manji is a fairly mysterious character, but part of that may simply be due to the anime adaptation skipping over some things. He was cursed with immortality and is currently atoning for his sins by saving 100 lives to match the 100 he took. However, while Manji is certainly immortal, his immortality isn’t absolute.

Kagehisa Anotsu is the main antagonist of the series. What makes him interesting, though, is that he’s not really a bad guy. His character falls into a grey area, and this is exemplified by the fact that Manji and Rin sometimes find themselves fighting alongside him. I could really write an entire article about Kagehisa, but I’ll leave it there for now.

Some of the supporting characters I really liked include Taito Magatsu and Makie Otono-Tachibana, two members of the Ito-Ryu, and Hyakurin, a member of the Mugai-Ryu. The Mugai-Ryu is a group formed by the shogunate in opposition to the Ito-Ryu.

Discussion (Major Spoilers)

Here’s where we get to the juicy stuff, so skip down to the conclusion if you don’t want to be spoiled.

Honestly, the main thing I think is holding Blade of the Immortal back is the quality of the animation. There were a few times when the animation was obscenely bad, and that definitely detracts from the series. Also, the pacing was a bit strange at times, shifting back and forth from slow to fast.

But the story was one of the best I’ve experienced in anime. Of course, I admit I have a bias towards samurai series and series with swordsmen in general, but I really liked Blade of the Immortal. All of the characters were complex and often fit into a moral grey area — and that includes Rin, the character driving the revenge plot.

For example, at the end of the series, Manji decides to allow Kagehisa to flee with his life. He doesn’t see the point in killing Kagehisa, especially since killing him won’t save Rin. But then Rin delivers the finishing blow to Kagehisa at the last second, cementing her role as a flawed protagonist.

Kagehisa Anotsu from the anime series Blade of the Immortal
Kagehisa Anotsu

I really thought Manji was going to let Kagehisa go and that Rin would eventually learn to forgive Kagehisa for killing her parents and Manji for allowing him to escape. And if there’s one thing I love, it’s when a twist genuinely catches me by surprise while staying true to the plot and characters.

Also, I need to mention the epilogue, because that really made me fall in love with this series even more.

The epilogue takes place like 70+ years after the events of the main story. It’s now the early 1900s, and Manji is still alive. He’s then introduced to a young girl — who turns out to be Rin’s granddaughter or great-granddaughter — and is tasked with keeping her safe.

Originally Manji thinks she looks familiar, but he can’t remember where he knows her from. So the girl then gives him a note from Rin and all his memories of their travels together come flooding back. It was a bittersweet ending because on one hand, we know the two of them parted ways, but on the other, Rin had such an impact on Manji despite his immortality.


Despite the fact that Blade of the Immortal is a solid 8/10 from me, I have a hard time actually recommending it. The aforementioned animation failures and pacing discrepancies would probably turn a lot of people off from the series. But if you can get through all 24 episodes, I can almost guarantee you’ll enjoy it.

The longer I’ve had to think about this series, the more I like it. And that’s really what makes it so difficult to recommend. Most people are looking for instant gratification from anime, and you won’t get that from this series.

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