by Takehito Koyasu makes his debut as Rouei, father of Dera, in a revealing flashback, and fans are already impressed by how perfectly his voice matches the character.
The latest episode of “Yomi no Tsugai” has given fans another intriguing piece of information about one of the story’s mysterious characters.
Episode 21, “The Zashiki Warashi and Higashimura,” began airing on August 29, 2026, and featured the first meaningful appearance of Rouei, the father of Ryu Tadera, also known as “Dera.”
Rouei has been mentioned as an important figure in the story, but much about him remains unknown. The episode finally allowed viewers to hear him speak in a flashback, revealing that veteran voice actor Takehito Koyasu will portray the character.
The casting immediately attracted attention online, particularly among fans of Hiromu Arakawa’s original manga. Many viewers praised the decision, with reactions including “Perfect casting,” “The interpretation is spot on,” and similar comments expressing satisfaction with Koyasu’s voice for Rouei.
The fact that Yuichi Nakamura voices Rouei’s son, Dera, has also created an amusing new talking point among fans. With Koyasu and Nakamura portraying father and son, viewers have jokingly described them as a “father-son duo with incredibly powerful vocal cords.”
Episode 21 Reveals More About Rouei’s Connection to Higashimura
Episode 21 focuses partly on the relationship between Yuru and his twin sister Asa, as the two characters finally have a more direct conversation about their respective thoughts and feelings.
As Yuru shares information he has learned, the mystery surrounding their past begins to become clearer.
One particularly important revelation concerns their mother and the barrier surrounding Higashimura.
Yuru explains that, apparently, Rouei was the person who taught their mother how to pass through the barrier when they left Higashimura 10 years earlier.
As soon as Asa hears this, she immediately recognizes the name.
“Mr. Dera’s father!?”
The brief exchange is significant because Rouei is not simply another person connected to the characters’ past. His knowledge of the barrier suggests that he may possess important information about Higashimura and the unusual circumstances surrounding Yuru and Asa.
For viewers who have been following the mystery from the beginning, the revelation creates another important connection between the characters and their hidden history.
Rouei Finally Speaks in a Flashback
Although Rouei has been discussed previously, the character has remained largely mysterious.
Episode 21 finally gives viewers a short flashback involving Rouei and his mate, the Zashiki Warashi.
Even though his appearance is still being kept largely hidden, the character now has a voice—and that voice belongs to one of anime’s most recognizable veteran performers.
Takehito Koyasu has built an extensive career playing characters with distinctive and powerful voices. His casting as Rouei therefore immediately attracted attention.
Rather than simply treating the character as another supporting role, the episode uses his brief appearance to emphasize that Rouei is connected to some of the story’s deeper mysteries.
The limited information surrounding him has also encouraged viewers to speculate about what kind of person he really is.
Fans Say Takehito Koyasu Was the Perfect Choice
The reaction from fans of the original manga has been particularly positive.
After Rouei’s voice was revealed, social media users praised the casting and suggested that Koyasu’s performance matched their image of the character.
Comments included reactions such as:
- “Perfect fit.”
- “The casting is spot-on.”
- “Koyasu is exactly what I imagined.”
- “His voice suits Rouei perfectly.”
For an adaptation of a manga with a dedicated readership, voice casting can be particularly important.
Readers often develop their own imagined voices for characters before an anime adaptation introduces an official cast. When the selected actor matches that mental image, the announcement can feel especially satisfying.
That appears to be what happened with Rouei.
Koyasu’s deep and recognizable voice also gives Rouei an immediate sense of presence, even though viewers have not yet been shown his complete character design.
Rouei and Dera Become an Unexpected Father-Son Pair
Another major talking point is Rouei’s relationship with his son, Ryu Tadera.
Dera is voiced by Yuichi Nakamura, another highly recognizable voice actor.
With Koyasu playing Rouei and Nakamura playing Dera, fans have naturally started comparing their voices.
Some reactions jokingly described them as a family with “incredibly strong vocal cords,” while others commented on how impressive it is to have two such recognizable voices portraying a father and son.
There were also humorous reactions along the lines of:
“What a father and son with incredible voices!”
Another fan jokingly remarked on the idea of Koyasu portraying the father of a son who is already in his 30s.
Although these comments are mostly playful, they highlight just how much attention the casting has received.
Rouei’s Face Is Still a Mystery
Interestingly, the episode still does not fully reveal Rouei’s face.
This means that the anime has introduced an important new voice without giving viewers the complete visual picture of the character.
That decision naturally raises even more questions.
What does Rouei actually look like?
What is his personality?
Why does he know how to pass through the barrier?
What is his relationship with the Zashiki Warashi?
And how much does he know about the events surrounding Yuru and Asa?
These questions could become increasingly important as the story moves forward.
Keeping Rouei’s appearance hidden also creates anticipation for his eventual full reveal.
Why Rouei Could Be Important to the Story
For newcomers, “Yomi no Tsugai” can initially appear to be a straightforward action-fantasy story. However, the series gradually reveals a much more complicated mystery involving twins, barriers, supernatural beings known as Tsugai, and the hidden history of the characters’ hometown.
Rouei appears to be connected to several of these mysteries.
His knowledge of the barrier is particularly important.
The fact that he taught Yuru and Asa’s mother how to cross the barrier suggests that he understood something about the rules separating Higashimura from the outside world.
That could make him an important source of information about the twins’ past.
At the same time, the story has deliberately revealed only fragments of his background, meaning viewers still have to wait for more answers.
“Yomi no Tsugai” Continues to Build Its Myster.y
The anime adaptation of “Yomi no Tsugai” is based on the manga by Hiromu Arakawa, the creator of the internationally acclaimed “Fullmetal Alchemist.”
The story follows twins Yuru and Asa, whose lives are dramatically changed after an unexpected incident disrupts the isolated world they know.
The series combines action, fantasy, mystery, and supernatural elements while gradually expanding its cast and mythology.
One of its major attractions is the way new information changes the viewer’s understanding of earlier events.
The introduction of Rouei is another example of this approach.
A character who was previously known mostly through references and hints has now been given an official voice, creating a new connection between the present story and the characters’ past.
Fans Are Looking Forward to Rouei’s Full Appearance
Because Rouei’s face has not yet been completely revealed, his casting announcement has only increased curiosity.
Fans now have an official voice to associate with the character, but they still do not know exactly how he will look or what role he will ultimately play.
That combination has made Rouei one of the characters viewers are watching particularly closely.
The relationship between Rouei and Dera is also worth following. With Takehito Koyasu and Yuichi Nakamura portraying the two characters, their eventual direct interaction could become one of the more anticipated scenes for fans.
Episode 21 of “Yomi no Tsugai” delivered more than another piece of character information. It strengthened the connection between the series’ present-day events and the mysterious history of Higashimura.
The revelation that Rouei taught Yuru and Asa’s mother how to cross the barrier could prove important as the story develops, while his brief flashback appearance finally gives fans an official voice for the mysterious character.
And the casting of Takehito Koyasu has been met with overwhelmingly positive reactions.
For fans of the original manga, the biggest takeaway is simple: Koyasu’s voice appears to match their image of Rouei extremely well.
The father-son casting of Koyasu and Yuichi Nakamura has also added an entertaining layer to the discussion, with fans already joking about the pair’s exceptionally powerful voices.
However, one major mystery remains: Rouei’s face has still not been revealed.
With his connection to the barrier, his relationship with the Zashiki Warashi, and his connection to Dera, Rouei could become increasingly important to the story.
For now, viewers will have to wait and see when the anime finally reveals the full truth about this mysterious father.
