The Boxer characters come down to three people. Yu is the blank-eyed teenager the story follows, K is the legendary trainer who sees a monster in him and feeds it, and J is the retired boxer the whole series is quietly building toward. Everyone else, from Ryu Baeksan to Injae, matters because of what they push Yu toward: feeling something, or feeling nothing.
Reviewing
The Boxer
That cast just got voices. On October 8, 2026, Crunchyroll announced a TV anime of JH's webtoon at New York Comic Con, with the four leads already cast. No release date yet, so for now you meet them in the manhwa. The table below pairs each one with where they first show up and who voices them.
The Boxer Characters at a Glance
| Character | Who they are | First appears | Anime voice (Japanese) |
|---|---|---|---|
| Yu | The protagonist, later a champion in nine weight divisions | Chapter 1 | Koki Uchiyama |
| K | Yu's trainer and the major antagonist | Chapter 1 | Tomokazu Seki |
| J ("J the Sun") | Retired boxer the wiki calls the true protagonist | Chapter 1 | Toshiyuki Toyonaga |
| Ryu Baeksan | School bully and Yu's first opponent | Chapter 1 | Kensho Ono |
| Injae (Jay in English) | Ryu's bullied classmate who takes up boxing | Chapter 2 | Not announced |
| Misaki | Coach of champion Takeda Yuto | Chapter 32 (shadowed in 28) | Not announced |
Debut chapters from The Boxer Wiki's character pages; cast from Crunchyroll's announcement.
Yu, the Protagonist Who Doesn't Care
Yu (left) and K, character art via AniList.
Yu (유) starts the story caring about exactly one thing, his pet cat. He takes hits because he can't be bothered to dodge them and doesn't react when someone obviously dangerous threatens him. Then K tests him with a full-power punch from behind, and Yu slips it while calmly tracking the fist with his eyes. K's own read is that Yu doesn't just react fast, he lives in his own "dimension of time."
Two years of training with K turn that into a pro career, and by the end Yu is a former world champion in nine weight divisions, working at an orphanage. The why is the dark part. The wiki's summary says that as a child he killed his abusive father, saw so much death that he became mentally unstable, and that K made it much worse. What pulls him back, bit by bit, is people: Injae, Takeda Yuto, Carmen, and finally J.
K, the Trainer Who Sees a Monster
K is the major antagonist and a legend in the sport: he's raised five world champions and only trains people his gut tells him will become one. He runs the Lions Boxing Club, and he considers Aaron Tide his masterpiece. With Ryu Baeksan, his instinct gave him the usual feeling. With Yu, it gave him something he'd never felt before, "bloodcurdling fear."
That fear doesn't stop him. K's backstory (a soldier who lost his wife and son, then decided boxing was the purest form of supremacy) explains his methods without excusing them, and he spends the series pushing Yu toward the monster he saw. The wiki leaves his fate after Yu's match with J unknown. We'd say he's the best-written character in the cast, and the reason the series reads like a thriller rather than a sports story.
J, the "True Protagonist"
J, also called J the Sun, is the character the wiki itself names "the true protagonist" of The Boxer, even though Yu is the one on almost every page. He meets Yu on the street at night, "when the stars were shining brightly in the sky," and what he says becomes a memory Yu keeps coming back to. In an r/manhwa thread about favorite lines, the only line one reader said they could remember was "The stars are shining just for you!"
J's record isn't glamorous, 36 wins and 26 losses over 62 fights, yet every one of those fights went down in history. He barely appears until he climbs into the ring to stop Yu's brutal fight with the Santorino brothers, then comes out of retirement to face Yu himself. He doesn't throw a punch until the very end, and that last one is a single touch that pulls Yu out of the darkness K pushed him into. It's the payoff the whole series is built for, so we won't say more.
Ryu Baeksan and Injae, the School Arc
Ryu Baeksan (left) and Injae, character art via AniList.
Ryu Baeksan is the school's bully and a natural. After two weeks in a gym he was already beating a pro boxer ranked third in the nation in sparring, and K called him a boxing genius. His superiority complex lasts until Yu beats him, and the wiki notes he cries "like a 5 year old for the first time in his life." Anime.com's write-up of the anime announcement calls him Yu's first opponent, so expect him early.
Injae, called Jay in the English edition, is Ryu's target: used as a seat, made to eat food Ryu's crew has ruined. Following his dad's idea of "a boxer's courage," he stands up to Ryu anyway and keeps getting back up until he's knocked out. Two years later he's training at Kim Tae-Pung's gym alongside Steel, and seeing Yu win his first pro fight makes him train harder. He's the early proof that Yu can affect someone, which matters more later than it seems at first.
Misaki and the Wider Ring
Misaki is a smaller role: the coach of Takeda Yuto, the light welterweight world champion. She's first glimpsed in Chapter 28 and properly appears in Chapter 32, watching Yu win the lightweight world title on TV. AniList lists her among the manhwa's supporting cast with Takeda Yuto, Carmen, Aaron Tide and the Santorino brothers, the names you'll meet once Yu turns pro.
The Boxer Anime Cast and Trailer
Crunchyroll's announcement names Koki Uchiyama as Yu, Kensho Ono as Ryu, Tomokazu Seki as K and Toshiyuki Toyonaga as J. Takehiro Kubota (My Happy Marriage) and Kang Wonyeong direct, Japan's breccia and Korea's STUDIO JEMI animate, and the series will stream on Crunchyroll. A release date wasn't announced. Our Boxer anime release tracker keeps the date, studio and trailer news in one place.
Readers are excited and nervous in equal measure. In the r/manhwa trailer thread, one of the top replies begged: "Please God just don't give this the Tower of God Season 2 slideshow treatment, I am begging."
Our Take on The Boxer Characters
Keep two directions in your head and The Boxer characters sort themselves. K pulls Yu toward dominance and numbness; Injae, Carmen and J pull him back toward being a person. Ryu is the first test, Misaki and the champions are the wider world, and J is the answer. If you haven't started yet, our The Boxer reading guide covers where the school arc ends and the pro career begins, and the full review has our verdict on how that ending lands.
How We Checked This
For this update we re-checked each character detail against The Boxer Wiki's pages for Yu, K, J, Injae, Ryu Baeksan and Misaki, the cast list and status on AniList, and the anime details in Crunchyroll's October 8 announcement. This pass removed a "former shut-in" line for Yu the wiki doesn't support, fixed J's debut (Chapter 1, not later) and dropped a FAQ answer about a web novel that doesn't exist. The Boxer is complete on WEBTOON; AniList counts 133 chapters.
Last reviewed: October 14, 2026
Related Reading
- The Boxer Review: our verdict on Yu's arc and whether the ending earns the build-up.
- The Boxer Reading Guide: where to start, how the arcs are split and where to read it legally.
- Manhwa Like The Boxer: what to read next if a numb, overpowered lead in a combat sport is what hooked you.
- Best Psychological Thriller Manhwa: The Boxer sits on this list for the K and Yu dynamic; the rest go darker.
- Best Completed Manhwa: more finished series you can read start to end without waiting.
