Seemingly a sailor who is amnesiac about all details of his personal life. For some reason, he has 4 testicles. The real identity of this character is unknown. The second chapter stated that the Jojolion protagonist's name

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could be Yoshikage Kira, however, it is later revealed that he is merely a doppelganger for the real Kira.

He was later given the name Jousuke by the Higashikata family, who took him in.

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However, DNA testing implies that they are nearly the same person.