Reading guide
List of Characters in the Chiikawa Movie | Voice Actors and Their Roles in the Original Manga
A guide to the six roles with confirmed voice actors in "Chiikawa the Movie: The Secret of Mermaid Island." Learn the casting for Chiikawa, Hachiware, Usagi, Momonga, Rakko, and Siren, plus where Shimajiro, the Mermaid, Furuhonya, Kurimanju, and Shisa fit in the Island Arc from volume 8 of the original manga—without spoiling the core ending.
Six characters have confirmed voice actors in the movie
As of August 18, 2026, the characters in "Chiikawa the Movie: The Secret of Mermaid Island" with confirmed voice actors are six: Chiikawa = Haruka Aoki, Hachiware = Masato Tanaka, Usagi = Ari Ozawa, Momonga = Yuka Iguchi, Rakko = Yuma Uchida, and Siren = Minori Suzuki. The movie was already released on July 24, 2026.
The source material is the Island Arc, collected in volume 8. In addition to the six roles above, Furuhonya, Kurimanju, Shisa, Shimajiro, and the Mermaid also appear in the Island Arc. Voice actors can be confirmed for the six roles mentioned earlier; the remaining five are marked "not listed in confirmed sources" in the table.
The Island Arc is a long-form story in which Chiikawa and friends travel to an island after Usagi brings back a recruitment notice promising "100x rewards and free meals." The liveliness of the journey by ship, the Mermaid's song encountered in a cave, and the strange happenings on the island layer one after another. Because the everyday companions and the people met on the island converge on the same events, it reads more easily if you track where each character enters the story, rather than trying to remember the sheer number of characters.
| Character | Voice Actor | Role in the Original Manga |
|---|---|---|
| Chiikawa | Haruka Aoki | The central figure who travels to the island. After being separated from friends, meets Shimajiro and gains a lead for the search. |
| Hachiware | Masato Tanaka | Stays close to Chiikawa, putting the Mermaid's song and the island's events into words and processing them. |
| Usagi | Ari Ozawa | The person whose recruitment notice set the journey in motion. Acts boldly in the cave and during the countermeasure. |
| Momonga | Yuka Iguchi | One of the group that travels to the island. During the song-based countermeasure, shows concern about the food. |
| Rakko | Yuma Uchida | Travels to the island with the group and joins in when danger approaches and in the companions' countermeasure. |
| Siren | Minori Suzuki | Appears alongside the Mermaid and tells of the event that took one of their companions—a driving force of the Island Arc. |
| Furuhonya | Not listed in confirmed sources | A manga character who travels to the island with Momonga and the others and takes part in the search and the countermeasure. |
| Kurimanju | Not listed in confirmed sources | Is put in charge as head chef for the curry-making that becomes the countermeasure against Siren. |
| Shisa | Not listed in confirmed sources | Serves as taste-tester during the curry-making, supporting Kurimanju's cooking. |
| Shimajiro | Not listed in confirmed sources | An island local who meets Chiikawa at a shellfish soup shop and helps the effort to find the lost companions. |
| Mermaid | Not listed in confirmed sources | A being who emerges from the cave's water surface and sings. Deeply connected to the companion Siren is searching for. |
Chiikawa, Hachiware, Usagi | The Three Who Travel to the Island
Usagi is the one who sets the journey in motion. The recruitment notice Usagi brings promises 100x rewards and free meals, and Chiikawa and Hachiware decide to join. What comes to pick up the three gathered at the shore is a vessel built from the neck and body of a white bird. The scene of boarding the unfamiliar ship with luggage in hand is a starting point that makes the island journey ahead feel immediate and real.
Upon arriving at the island, Chiikawa collapses in poor condition, and Hachiware stays close, searching for something edible. Even in the middle of a lavish feast, Hachiware worries about a friend, while Chiikawa presses on through the island while dealing with their own health. The small exchanges between the two convey that this is not a journey that reward money and feasting alone can carry forward. Usagi pushes ahead as always, and the three's differing temperaments create the distinctive rhythm of the Island Arc.
In the cave at night, the three ride a small boat onward and hear the song of the Mermaid who emerges from the water's surface. Hachiware and the others take it as a song about the island's food and join in with their own voices. Just after song closes the distance where words could not, a huge Siren appears at the water's surface, and the scene abruptly turns into a tense chase after the small boat. Though Chiikawa, Hachiware, and Usagi are in the same boat, each faces the sudden danger with their own reaction. The whiplash of a fun food song switching into a pursuit is a memorable turning point in the first half of the Island Arc.
Momonga, Rakko, and Furuhonya | Companions Who Join Up from Separate Movements
Momonga, Rakko, and Furuhonya are also traveling companions named in the Island Arc of volume 8. Easy to overlook if you only follow Chiikawa's trio, but as the search expands, Furuhonya acts alongside Hachiware, Usagi, and Momonga, heading to areas away from the water. With the group splitting into multiple teams, the unease of not knowing where danger lies on the island continues to grow.
In the scene where everyone sings as a countermeasure, Momonga appears reluctant while asking whether joining means getting to eat something tasty. Rakko responds to that question, while nearby Usagi sings at full volume and Kurimanju adds sound by flicking canapés from a can. It's delightful how they don't push through with bravado alone, folding even concern for food and half-hearted feelings into a single plan.
Furuhonya also appears in the scene where Chiikawa eats at Shimajiro's shop. Momonga, Furuhonya, and Rakko each react differently despite sharing the same goal, giving expression to this character-heavy long-form arc. Momonga and Rakko, whose movie voice actors are confirmed, also show different reactions within the same plan. The movements of the three, including Furuhonya, broaden the flow from the search to the reunion.
Siren and the Mermaid | The Beings Who Drive the Island Arc's Events
The Mermaid emerges from the cave's water surface and sings about how delicious the island's food is. Small companions float nearby, and Chiikawa and friends respond in song. Meanwhile, Siren appears immediately afterward in a massive form and chases the small boat. Rather than lumping the Mermaid and Siren together as the same being, watching the relationship between the singing Mermaids and the Siren who moves to protect companions is the quickest way to grasp the situation in the original manga.
By the campfire, Siren tells of how one of the Mermaids they originally lived with was lost, leaving them unable to sing as a trio. When Hachiware mentions remembering a story about Mermaids being eaten, Siren takes it to mean that someone on the island may have been involved. From this, tension arises between those searching for the Mermaid and the island residents under suspicion. Even without knowing the core ending, you can hold onto the fact that Siren's actions begin from the absence of a companion.
The only voice actor explicitly named for the movie is Minori Suzuki as Siren. On the manga side, the encounter in the cave and the circumstances of Siren searching for a companion form the entry point of the two beings' relationship. Even without touching the core ending concerning the Mermaid, the contrast—Mermaids who sing versus Siren who mourns a missing companion—lets you grasp the relationships.
Shimajiro | The Island Figure Who Aids the Search from His Shellfish Soup Shop
Shimajiro is the person Chiikawa, separated from friends, finds in the forest. Following a roadside sign leads to a shop serving shellfish soup, where Shimajiro is eating inside. After the chase by Siren and the separation from companions, the appearance of a shop with food and a calm counterpart loosens the tension for a moment. It's a clear-cut introduction, with the name Shimajiro and the shop presented together.
To Chiikawa, weakened by exhaustion and hunger, Shimajiro recommends curry and shellfish soup. Even while eating, Chiikawa worries about the others, and Furuhonya is also present in the shop. Not ending things with a meal, Shimajiro takes Chiikawa's concern to heart and offers information leading to the companions' whereabouts. The flow from a calm dinner table into the search shows Shimajiro's dependability well.
Using as a lead the story that islanders who went to gather shellfish spotted a Mermaid deep in the cave, Shimajiro guides Chiikawa to the water. Then he decides to dive in himself to check, pushing the search forward. As a guide, he heads willingly into dangerous places. The sequence of "welcoming at the shop, feeding, then going to search" shows Shimajiro's kindness and initiative one after the other.
Kurimanju and Shisa | The Manga Cast Who Handle the Curry-Making
What begins as the means to stop Siren is spicy curry-making by the island residents and traveling companions. Kurimanju lines up as head chef and Shisa as taste-tester, Chiikawa and Hachiware gather ingredients, and island residents carry crops from the fields. Not only those who fight but also those who cook and those who check the flavor have roles, so the many characters converge on a single purpose. That the countermeasure to the crisis is curry is fitting for the Island Arc, where food repeatedly drives the story.
In parallel with preparations to deliver the curry, Usagi moves from whistling to loud song, and Kurimanju layers in the sound from a can. Momonga and Rakko are nearby, and even the red-tailed Mermaids join their voices. That Chiikawa, Hachiware, and Usagi are joined by longtime companions, people met on the island, and the Mermaids gives the second half of the Island Arc its richness. There's a swell of excitement in everyone's small roles in the cooking and singing coming together as one countermeasure.
Kurimanju and Shisa support their companions from the side that completes the dish. It's fun to see their separate specialties—head chef and taste-tester—unite around a single great pot. Those who got to know the characters through the movie can go to volume 8, and those who want to follow appearance order and the original posts can head to the Island Arc page, where they can trace how each character converges without the core ending being spoiled.
Frequently asked questions
Which characters in the Chiikawa movie have confirmed voice actors?
As of August 18, 2026, the confirmed ones are Haruka Aoki as Chiikawa, Masato Tanaka as Hachiware, Ari Ozawa as Usagi, Yuka Iguchi as Momonga, Yuma Uchida as Rakko, and Minori Suzuki as Siren.
Who is the voice actor for Siren?
Siren is voiced by Minori Suzuki. In the original Island Arc, Siren tells of losing one of the Mermaid companions and appears as a driving force behind the island's events.
What roles do Shimajiro and the Mermaid play in the original manga?
Shimajiro is an island local who offers food to Chiikawa, separated from friends, and helps with the search. The Mermaid emerges from the cave's water surface and sings, and is deeply connected to the companion Siren is searching for.
If I want to read the movie's characters in the manga, which volume should I get?
The source Island Arc is collected in volume 8. To follow the characters including Shimajiro, Siren, and the Mermaid in publication order, you can also read the original posts from the Island Arc page.