When we first meet Koichi Hirose, he’s just a regular high school kid in the quiet town of Morioh. He’s small, pretty timid, and often doubts himself. Compared to the louder, flashier characters in JoJo, he might seem a little plain. But that’s what makes his transformation so amazing. As the story goes on, Koichi becomes a key part of the team, growing stronger and braver through each challenge. By the end of Part 4, he’s confident, capable, and deeply respected by both friends and foes.
Koichi Hirose is notably short, standing at just 157 cm (around 5’2″).
Koichi’s Stand
A big part of Koichi Hirose’s journey is tied to his Stand, Echoes (sometimes called Reverb in certain translations). Like Koichi himself, Echoes starts out small and simple but evolves into something much more powerful. It changes over time, mirroring how Koichi grows throughout the story.
Echoes Act 1
When Koichi first unlocks his Stand, it’s not very strong. Act 1 can attach sounds to people or objects, making those sounds repeat over and over. For example, if he uses the sound “Boom!” on an enemy, they’ll keep hearing it nonstop, which can distract or confuse them. It might not seem very dangerous, but Koichi uses it in clever ways, showing that brains can sometimes beat brawn.
Echoes Act 2
As Koichi becomes more confident, Echoes evolves into Act 2. This version lets him attach words to objects, and those words physically come to life. If he writes “Sizzle,” for example, the object heats up as if it’s burning. This upgrade shows how much Koichi is starting to believe in himself.
Echoes Act 3
Echoes reaches its final form, Act 3, when Koichi faces off against the dangerous Yoshikage Kira. Act 3 is a humanoid Stand that can talk and fight alongside Koichi. Its main ability, “3 Freeze,” makes objects super heavy, effectively stopping enemies in their tracks. This form represents Koichi’s peak—he’s no longer hesitant or afraid. He’s willing to stand up to even the toughest opponents, proving how far he’s come.
Koichi’s Key Relationships
The people around Koichi Hirose are really important in shaping who he becomes. Let’s dive into some of his most important connections.
Koichi and Josuke Higashikata
Josuke, the main hero of Part 4, is one of Koichi’s closest friends. Their friendship is built on trust and mutual respect. Josuke often steps in to protect Koichi when things get dangerous, but he also admires how smart and resourceful Koichi can be. Together, they balance each other out, Josuke’s boldness pushes Koichi to be braver, while Koichi’s calm, thoughtful nature helps keep Josuke grounded.
Koichi and Jotaro Kujo
Jotaro, the quiet and serious hero from Part 3, takes a surprising interest in Koichi. At first, it might seem odd, Jotaro is tough and stoic, while Koichi is small and unsure of himself. But Jotaro sees Koichi’s potential right away. He respects Koichi’s intelligence and courage, even when Koichi doubts himself. Over time, Koichi looks up to Jotaro as a mentor, while Jotaro relies on Koichi’s creativity and problem-solving skills.
Koichi and Yukako Yamagishi
Yukako is one of the most complicated people in Koichi’s life. At first, her obsession with him is terrifying, she kidnaps Koichi in a twisted attempt to make him love her. But instead of giving in to fear or anger, Koichi handles the situation with surprising compassion. He helps Yukako see her flaws and become a better person. By the end of the story, their relationship turns into something more genuine, with mutual understanding and even hints of romance.
Why Does Jotaro Like Koichi?
Jotaro is not someone who gives out compliments easily, so his admiration for Koichi says a lot. While Koichi isn’t the strongest fighter, he brings something unique to the team. His intelligence, creativity, and willingness to put himself in danger for others earn Jotaro’s respect. Koichi’s loyalty and resourcefulness often turn the tide in battles, proving that you don’t need brute strength to be a hero.
What Does Koichi Hirose Do in Part 4?
Koichi has a huge impact on the events of Diamond is Unbreakable. Here are some of his key moments:
- Meets Josuke and Jotaro: Koichi gets caught up in the world of Stand users when Jotaro arrives in Morioh.
- Unlocks His Stand: After being struck by the Stand arrow, Koichi develops Echoes, which evolves as he grows stronger.
- Outsmarts Tamami and Hazamada: Koichi cleverly defeats enemies like Tamami (The Lock) and Hazamada (Surface), showing his quick thinking.
- Fights Yukako: Koichi uses Echoes Act 2 to escape Yukako’s clutches and helps her become a better person.
- Stands Up to Rohan Kishibe: Despite Rohan’s overwhelming Stand, Heaven’s Door, Koichi finds a way to outwit him.
- Helps Defeat Yoshikage Kira: Koichi plays a major role in identifying and stopping Kira. He uses Echoes Act 3 to immobilize Kira’s Sheer Heart Attack, giving Jotaro and Josuke time to act.
Koichi in Golden Wind
Koichi also makes a brief appearance in Part 5, Golden Wind. At Jotaro’s request, Koichi travels to Italy to investigate Giorno Giovanna, the son of Dio Brando. Koichi confronts Giorno and witnesses his Stand, Gold Experience, in action. After deciding that Giorno isn’t a threat, Koichi reports back to Jotaro and leaves the rest of the story to Giorno.
