Koichi Hirose/Games

Vento Aureo (PS2)
Koichi was planned to be in the GioGio PS2 game, likely as a playable character as there are beta pictures of him appearing in the game (such as one of him appearing with the main characters of Part 5 and in another one looking for Giorno and his stolen luggage). However, for unknown reasons Koichi was removed from the game, with no trace of him even in the game's Gallery Mode (unlike other characters, such as Risotto Nero or Leaky-Eye Luca, who do not appear in Story Mode but have viewable characters models regardless).

In canon Part 5, Koichi has a confrontation with Giorno over his stolen items and later helps him fight against Black Sabbath. As he was absent from the game, the Story Mode begins with the narrative skipping to Giorno on the tram being confronted by Bucciarati in Chapter 1, and in Chapter 3, Giorno fights Black Sabbath by himself.

All Star Battle (PS3)
Koichi makes his playable debut in the PS3 game and was confirmed along with Akira Otoshi. Koichi is voiced by Romi Park, who previously voiced Giorno Giovanna and Gold Experience Requiem in the aforementioned PS2 GioGio game.

Along with Enrico Pucci, Kosaku-Kira, Johnny Joestar, Hol Horse, and Giorno Giovanna, Koichi is a character who can utilize more than one Stand during a match as part of his moveset. In gameplay, Koichi uses all three forms of Echoes as part of his moveset, unlike Johnny or Pucci, who need to evolve their Stands during combat.

As one of the majority of playable characters with the "Stand" Style, Koichi can turn Echoes ACT3 on/off, changing movesets, as well as having access to the Stand Rush ability returning from the Capcom game, being able to attack in conjunction with his Stand.

During a fight, Koichi can use several different abilities that were featured in Diamond is Unbreakable.


 * Throw - Whooooosh!: ACT2 hits the opponent with a "Whooosh!" SFX, sending them flying.

While Echoes ACT3 is off:


 * Enough!: Koichi runs forward and swings with all his might. If the punch connects, the opponent is sent flying upon impact. Koichi's skills can be performed instantly following this move. (Comboable)
 * I'll never forgive you!: Koichi summons ACT1 to fly forward and assault the opponent with loud SFX. This move has a follow-up. (Comboable through Puttsun Cancel)
 * Cicada's cry etched in stone: ACT1 increases the number and volume of SFX to the point where the opponent collapses. (Comboable)
 * Sizzle!: ACT2 throws its tail end in an SFX that arcs. If it hits the opponent, they will catch fire and gradually lose health over time for a few seconds. This move doubles as an anti-air. (Comboable through Puttsun Cancel)
 * Kaboom!: A counter. Koichi crosses his arms and glares, and if the opponent hits him during that moment, SFX by ACT2 will reveal itself on Koichi and they will be blown back.
 * Boing!: ACT2 slaps an SFX on the ground in front of Koichi. If the opponent comes in contact with it, they'll be blown upward into the air and take slight damage upon landing (Comboable). If Koichi himself touches it, he will leap high into the air, allowing him to evade many of the opponent's attacks or set up his own attacks from the air.

While Echoes ACT3 is on:


 * Hit them, ACT3!: ACT3 flies forward, rapidly punching the opponent and pushing them away. (Comboable through Puttsun Cancel)
 * S-H-I-T: ACT3 flies into the air and comes down punching with the 3 Freeze effect active, downing the opponent. This move doubles as an anti-air and inflicts the 3 Freeze effect for a short duration. A Stand Rush skill that Koichi can disconnect from to attack the opponent while it is executing. (Comboable through Puttsun Cancel)
 * This air pressure?!: ACT3 swiftly moves in front of Koichi and unleashes an intense burst of air capable of knocking both him and the opponent back. This skill can interrupt an opponent's combo, and unlike other skills of similar effect, does not spend any amount of the HHG. However, Koichi is harmed as well for even more damage. Koichi may recover up to half of the lost health over time, but only if he does not receive any more damage during the process.

Koichi's HHA, GHA, or "S-H-I-T" inflicts 3 Freeze. The opponent is made heavier as a result of ACT3. This results in them moving much slower and being unable to jump for a period of time, forced into a constant crouch. While the effect cannot be broken by hitting Koichi or gaining enough distance, it has a relatively short duration, slightly altered based on the attack that generated it.

Koichi's HHA, "Echoes ACT3: FREEZE!!", sends ACT3 flying forward, rapidly punching the enemy with the Freeze effect active and pushing them away for an extended period of time, with the final hit knocking them down. The HHA does not require an initial hit to connect in order to work, and will not stop until it finishes or Koichi is interrupted. The HHA inflicts the 3 Freeze effect for a medium-length period of time.

Koichi's GHA, "I'm really getting stronger?!", starts with him summoning ACT1 to throw a "BAM!" SFX. If it lands, the opponent is assaulted by SFX loudly repeating itself enough to make them cover their ears. ACT2 flies in and places a "KaBOOM!" SFX under them, blasting them high into the air. The GHA finishes with ACT3 appearing above the opponent and performing a barrage of punches while activating 3 Freeze, making the opponent smash into the ground on landing. The GHA inflicts the 3 Freeze effect for a long period of time.

Aside from being a playable character, Koichi also appears on the stage "Kira Estate" as a background character, if he himself is not one of the two fighters, along with Okuyasu. Koichi also appears as the auto-save icon, with his face under the effects of Heaven's Door as the pages flip.

Koichi uses unique dialogue before a fight with Jotaro or Giorno, telling the latter that he wants his suitcase luggage back, recreating their antagonistic dynamic during early Part 5 before they leave on good terms.

Koichi possesses two alternate costumes, the first being the pajamas he wore during Yukako's introductory arc and his second one being his T-shirt with the LUCKY.CO logo on it that he wore during his assistance in Josuke's battle against Highway Star.

Koichi also won the first place in his League Group in the All Star Battle League, beating fan favorites such as Giorno, Jolyne, and Gyro. He even managed to reach to the semi-finals matches, but ultimately lost to Jotaro.

Eyes of Heaven (PS3/PS4)
Koichi was confirmed for the game alongside Yukako.

Once again Koichi is voiced by Romi Park and his main color scheme is the same from the previous game.

Since most of the game's animation, effects, and attacks were reused from All Star Battle, Koichi's style of play remains mostly the same; focusing on using a variety of abilities across Echoes' different ACTs.

As a Stand User, Koichi is one of many characters with wildly varied abilities that grant him uniqueness in battle.


 * Style Action - ACT1/ACT2/ACT3: Koichi cycles Echoes through its different ACTs, completely changing the skills and attacks available to him. Each ACT specializes in a certain area: ACT1 grants useful buffs and debuffs despite its low attack and skill count; ACT2 focuses on ranged attacks and traps, being able to throw its tail as a projectile in exchange for melee; ACT3 grants access to normal melee combos and conventional moves involving its punches and 3 Freeze.

While ACT1 is active:


 * Trust me!: ACT1 throws an SFX with some homing capabilities at his partner, and if it connects, they are granted a boost in stamina and the Dual Heat Gauge is filled by a small amount. This skill is unavailable if Koichi's partner is out of range. If partnered with Yukako, the skill's effectiveness is increased.


 * I hate you!: ACT1 throws an unblockable SFX with some homing capabilities at an opponent, and if it connects, the target's defense and stamina gauge is lowered, and the enemy team loses an amount of their own Dual Heat Gauge. If fighting against Yukako, she is immune to this effect while her "I can't hear you!" passive skill is active.

While ACT2 is active:


 * Boing!/Whooooosh!: The attack unleashed is dependent on whether or not the movement stick is tilted in a direction while the skill is inputted. If inputted from neutral, ACT2 slaps an SFX on the ground in front of Koichi. If an opponent comes in contact with it, they'll be blown upward into the air taking no damage. If Koichi himself touches it, he will leap high into the air, allowing him to evade many of the opponent's attacks or set up his own attacks from the air. If inputted while moving, ACT2 instead swings its tail horizontally, placing a different SFX on a wall (of note is that the in-game description erroneously claims the surface to be the ground) if available or dealing small damage to an opponent in-range otherwise. If an opponent comes in contact with the SFX, they'll be blown backward a great distance, still taking no damage.


 * Sizzle!: ACT2 utilizes an offensive SFX from its tail to catch opponents on fire and cause them to gradually lose health. The execution of the skill is dependent on whether or not the movement stick is tilted in a direction when it is inputted. If inputted from neutral, ACT2 throws the SFX in a straight line with an indefinite range as a projectile. If inputted while moving, ACT2 slaps the SFX on the ground where it becomes a trap. If the skill is executed in the air, the projectile version is performed by default.


 * Bahyoo!: ACT2 whips its tail outward with it semi-transformed into an SFX. If it connects with an opponent, they take moderate damage and are sent flying a large distance away.


 * EX - Sizzle!: The SFX gains a damage boost, and the projectile version of the skill flies faster.

While ACT3 is active:


 * 5-METER RANGE ACHIEVED. S-H-I-T!: ACT3 generates a short gravity field around itself, dealing a small amount of damage to opponents and immediately downing them. This inflicts 3 Freeze's effect, dubbed Heavy. Once in effect, targets will be unable to jump, and their movement speed is much slower for a period of time. Similar to All Star Battle, if Heavy is inflicted on Kira's Sheer Heart Attack, it will be immobilized for a period of time.


 * Echoes 3 Freeze!: ACT3 flies forward, unleashing a barrage of 8 punches and pushing opponents away while inflicting Heavy.


 * Wh-What is this wind?!: ACT3 swiftly moves in front of Koichi and unleashes an intense burst of air capable of knocking both him and the opponent back. This skill is unblockable and creates a large amount of distance if successful. However, Koichi is knocked down and takes a small amount of damage in the process.


 * EX - 5-METER RANGE ACHIEVED. S-H-I-T!: The duration of the Heavy effect inflicted is increased.

JoJolities

 * Trust me!: Koichi must connect "Trust me!" twice. (200 Points)


 * You're no match for Echoes ACT2!: Koichi must connect "Sizzle!" twice.(200 Points)


 * My ACT3 is awesome!: Koichi must inflict Heavy 3 times. (300 Points)


 * ACT3 Freeze!: Koichi must perform a Dual Combo Finish. (500 Points)


 * I have protected you as ordered.: Koichi must Retire an opponent with a Dual Heat Attack. (800 Points)

Dual Heat Attacks

 * Solo - I'm really getting stronger?!: Identical to its performance in All Star Battle, though executes faster for the sake of brevity. It also still inflicts Heavy afterward.


 * With Josuke - Dorara Rush ×2: Koichi has Echoes ACT2 place SFX of Crazy Diamond's Stand Cry ("DORARARA!!") directly under the opponent's feet. He then prompts Josuke to attack, watching as he jumps high into the air until he is directly above the opponent. The SFX then activates, creating artificially-made fists to attack from below as Crazy Diamond punches the opponent from above, hitting them from both sides. This is the only DHA available to Koichi that does not involve 3 Freeze and therefore does not inflict Heavy.


 * With Yukako - Invincible Heroine: Koichi uses 3 Freeze to make the opponent heavier, then Yukako wraps them in her hair before attempting to fling them around. Despite struggling with the increased weight of the opponent, she successfully slams them into the ground four times before raising them extremely high up into the air and launching them into the ground one more time hard enough to generate a shockwave.


 * With Rohan - We're best friends!: Koichi uses 3 Freeze to make the opponent heavier, before Rohan uses Heaven's Door to write in the opponent "My weight will increase 10-fold.", combining the effects and multiplying their weight to such a degree that it causes them to slam face-first and sink into the ground with enough force to generate a crater.

In the post-credits scene of the new JoJo timeline where most of the fallen allies (including the actual Kosaku Kawajiri) are now alive well (and Joshu's relationship Part 8 Josuke improves), during the retelling story of Part 4's first chapter where he met Jotaro, Koichi claims to experience deja vu, and that he met a younger Jotaro somewhere before.

Tournament
He is paired with Will A. Zeppeli in the Eyes of Heaven Tournament but was eliminated in the preliminaries by Jonathan Joestar and DIO.

Last Survivor (Arcade)
Koichi was one of the characters first confirmed during the game's announcement.