Hayato Kawajiri

Hayato is reserved and reluctant to discuss his problems, even with his parents. He spends much of his time alone, reading manga with headphones on and watching the household through recording devices. His family relationships are distant, but his apparent detachment does not mean that he is indifferent to his mother's safety.

Under pressure, Hayato proves observant, resourceful and remarkably brave. He cannot see Stands, so he works from changes in behavior, physical evidence and the effects of abilities rather than relying on powers of his own.

Small inconsistencies alert Hayato to the change in Kosaku: the unfamiliar man behaves differently and even practices his father's signature. Hayato's surveillance eventually exposes Kira's violent secret. He tries to use his recordings as leverage, but confronting the murderer puts his own life in immediate danger.

Kira kills Hayato during their confrontation. When the Arrow gives Kira a new ability, Bites the Dust, its time-reversing effect restores Hayato to life. Hayato then finds himself trapped in a repeating morning, with the people who discover Kira's identity through him being killed.

Hayato remembers the repeated mornings, which lets him compare events and search for a way out. Simply telling the others Kira's name would endanger them. Instead, he arranges for Josuke to arrive in time to hear Kira identify himself.

He also attempts to attack Kira with Stray Cat's compressed-air shot. A watch protects Kira from the attack, but Hayato's backup plan succeeds: Josuke appears, and Kira must recall Killer Queen to defend himself. That decision ends the loop before its scheduled deaths can occur.

Hayato continues to assist Josuke even though he cannot see the Stands fighting around him. When Kira turns the wounded Okuyasu into a bomb, Hayato sets it off so that Josuke can approach him; Crazy Diamond repairs Hayato before the explosion can kill him. He also shares what he has learned about Kira's bomb ability and movements.

Kira is eventually defeated, but Hayato's real father cannot return. His final exchange with Shinobu leaves that loss unresolved within the family, giving his victory a personal cost as well as protecting Morioh.