Naoto Tachibana/Relationships

Takemichi Hanagaki
As an adult, Naoto functions as Takemichi's time-leaping trigger and uses his police connections to supply information about Toman's past. Although he initially viewed Takemichi as a pathetic person and wonders why his sister fell in love with him, he begins to respect Takemichi for his perseverance and strength in their shared mission of saving Hina.

Throughout Takemichi's numerous failures, he reassures Takemichi of his impactful actions, encouraging him to continue in the mission. Naoto eventually comes to see Takemichi as a hero and values his life, shown in events such as killing Mikey to ensure Takemichi's safety and sustaining bullets in Takemichi's place. Because Naoto feels indebted to Takemichi for saving both him and his sister, he continues to supply information, such as intel on Bonten, to him; Naoto also obliges Takemichi's request to time-leap after the mission is complete.

Hinata Tachibana
Naoto dedicates his life to saving Hina after his encounter with Takemichi, initially driven to achieve this by any means, even killing Toman's adolescent leaders. After her second death, Naoto wails in agony at her funeral.

As a child, he and his sister have a typical sibling relationship. He is unamused by Hina and Takemichi's romantic moments, often uncomfortably interrupting them to comment on their flirting.

Masato Tachibana
Because of his father's busy work schedule, Naoto resented him, as he was rarely home. However, after his first encounter with Takemichi, Naoto becomes interested in his father's profession as a police officer.

Tetta Kisaki
Naoto has a lot of hatred for Kisaki and that's because he is his older sister's killer. They met in a timeline of the future and Naoto throws himself in front of Takemichi to receive the shots. Naoto wants revenge and demonstrates his hatred for Kisaki, wanting to finish him off.