Her "best friend." Yoshino is very attached to her puppet, Yoshinon and believes that it is real, and will get extremely (and dangerously) emotional when Shido insists that she is doing ventriloquism (for the most part, she seems unaware of it) or when something happens to it. Yoshinon is "the person that I [she] want[s] to be" and it is her "hero." As a spirit, Yoshino was dependant on Yoshinon and he somewhat acted as her mental support.
Yoshino’s new hero, her savior, and the next person she depends on besides Yoshinon. She respects him a lot and looks up to him or views him in a brotherly manner. Yoshino trusts him a lot and is grateful for him for finding Yoshinon. This trust is what allowed Shido seal her powers.