Koichi is a meek first-year highschooler who finds himself embroiled in the world of Stand users as he befriends Josuke Higashikata. He eventually becomes a Stand user himself and wields the sound-manipulating Stand, Echoes, becoming more courageous in the process. One of Koichi's constant traits is his friendliness and overall politeness toward any stranger and acquaintance. Having a gentle heart, Koichi usually doesn't seek to harm his opponents, notably having saved Yukako from death even though she wanted to kill him before,[11] and briefly fighting Giorno Giovanna without the strength to kill, which inadvertently saved him.[12] However, Koichi's friendliness disappears on the rare occasions he is angered, and he becomes more abrasive, violent and vulgar. Complimenting his childlike appearance, Koichi also possesses a rather cheerful personality. He finds wonder in the littlest and most mundane things and has little trouble befriending people. Because of this, he is usually easily pressured into an interlocutor's demands, such as Tamami Kobayashi effortlessly extorting him, or Rohan pushing him into spending time with him.Much like any ordinary teenager, Koichi is interested in more accessible distractions. He is a great fan of Rohan Kishibe's manga Pink Dark Boy and plans to visit Disneyland Paris but expresses no interest in "old" countries such as Italy. The mix of his gentleness and courage make Koichi an extremely likable individual, earning the friendship and respect of the vast majority of the cast including Josuke Higashikata, Tamami Kobayashi, Toshikazu Hazamada, Rohan Kishibe, Yukako Yamagishi, Aya Tsuji, and Jotaro Kujo. After a difficult start in his relationship with Yukako, due to her kidnapping Koichi, he eventually fell in love with Yukako's tough and unforgiving personality. His love was such that he was willing to be blinded forever in case Yukako became ugly, so as to ease her pain.
