|Manga||331. Reversible Invasion|
|Manga||382. Lightning Counterstrike|
He is a 25 year old hunter from Gunma, who responded to Kurono's and Reika's call, to join the Tokyo team and fight against the invading aliens. He appears to be proficient with using the Gantz Sword as there are two holstered onto his legs, and later on, his movements in combat are so fast that he was a blur and Kurono couldn't keep up with watching Kaiji in battle. In chapter 333 he informs Kurono that Gantz can no longer heal any form of injury.
Chapter 338 shows him assisting the team in combat by dual wielding the swords with an apparent amount of skill.
In chapter 347 he is present when the spores of light had escaped from the object that the children were holding. He and the others get down on the ground to avoid them when he notices that one of the spores had entered Sekine's back. He calls out to the rest of the team that Sekine was in trouble. When a bulge appears on Sekine's arm, they were told not to allow it to get to his head. Sekine asks Kaiji to cut off his arm in order to stop it from spreading. Kaiji after a moment's hesitation, cuts off Sekine's arm, but watches in horror as it was too late to stop it from spreading, killing Sekine in a grotesque manner.
In chapter 349, a horde of skeleton-like aliens appears, which are immune to even the powerful Z-Gun. They are strong enough to easily take out the hard suits in one hit. All others seem to despair, one even crying saying it was hopeless. But Kaiji goes forward armed with two Gantz swords, and manages to cut the head off of one of them, while losing one of his swords in the process. He later helps defend Kei with the rest of the Katastrophe team from Eeva Gund. He manages to fight toe-to-toe with him for a while. A notable achievement. He was even able to land several attacks on him. Unfortunately for him, Eeva was able to counterattack, slicing Kaiji in half and killing him. He is soon revived and transfered back home, however, after Kurono and Kato defeat Gund.
Personality and Fighting Style Edit
He seems moderately laid back, he seemed to make light of the mission to invade the aliens spaceship alongside the Tokyo team and others. He even suggested that it was a suicide mission asking "If everyone was ready to die." He is also considerate, when a fellow team member, Sekine asked it to cut off his arm, he double checked, despite the situation his team mate was in. He possesses a sense of humor, joining all the other men to urinate in an alien-human processing plant. He is near-fearless, when Kei and the Katastrophe team began to fire their weaponry at powerful aliens, despite the guns taking no effect Yoshikawa charged at the aliens with his swords at the ready.
Yoshikawa prefers using two swords as his weapons of choice, and appears to be ambi-dextrous, he is one of, if not the most proficient sword users seen thus far in the series. He fought powerful aliens whose durability was enough to break one of his Gantz swords, using just the one, and found the weak point at their neck. He is incredibly fast as even Kei - renowned for his speed, had trouble spotting his movements. It was hinted at by Toshio he was a "monster" in terms of fighting skill, alongside Kei, Kaze, Mary Mclane, and Kato. Using his swords he was able to fight and push back the fast, Eeva Gund, even dodging his frighteningly quick blows. And deliver several vital slashes against him, putting him on the ropes. During his few fights, he has undoubtedly shown one of, if not, the greatest display of swordsmanship in the entire Gantz series, landing more blows, and injuring the deadly Eeva Gund, more than any other of the combatants who engaged him, including Kei, Kato and dozens of highly skilled Americans, the likes of which, couldn't even touch him.