Koichi Hirose is a key character from the anime series "JoJo no Kimyou na Bouken," also known as "JoJo's Bizarre Adventure." He appears in the third part of the series, "Diamond is Unbreakable." Koichi is an unassuming high school student who initially seems timid and reserved. However, he becomes a vital ally to the protagonist, Josuke Higashikata, as they battle various Stand users in their town. Koichi's Stand, Echoes, evolves throughout the series, significantly enhancing his combat abilities and playing a crucial role in confronting the series antagonist, Yoshikage Kira.