Murasame Shizu

The ghost of a girl who died in the old abandoned school building 400 years ago, Oshizu is sincere, kind, and very curious about the modern world, but has a severe fear of dogs, likened to Haruna Sairenji's level of fear to the supernatural. When frightened, she can emit blasts of mental stress, blowing apart various objects and surroundings, but is also capable of manipulating others through sheer willpower. Since her meeting with Rito and the others, she begins exploring the world outside the old school building. Oshizu is aware of Haruna's crush on Rito by her ability to sense feelings while possessing another person and becomes very supportive towards cheering Haruna into confessing her feelings to him.

Oshizu "returns" to the living, after Ryoko Mikado creates a prosthetic body for her to inhabit, built with biological qualities (looking and feeling like an actual, human body). However, she occasionally "disconnects" during brief moments of excitement. She currently works as a nurse for Ryouko. In the first anime, Oshizu is not given a new body and her presence is limited, while she has her body as she does in the manga for the OVA releases and the new anime.

She appeared in Mayoi Neko Overrun! as a customer (with Haruna)

Ryoko Mikado
Mikado was the one created her artificial body for her to walk among others, Oshizu now lives with her and even works at her clinic as her nurse (she can be clumsy though). Oshizu can be very obidient to her, like when Mikado asked Rito to rub sun tanned lotion on her she used her powers to force him to do it.

Haruna Sairenji
Originally Haruna had great fear of ghosts and anything supernatural but while becoming closer to Oshizu her fear seems to have lighten up (although she still shows fear of it). Oshizu knows about Haruna's feelings toward Rito and often supports and encourages her (going as far to using her own powers) to confess to Rito how she feels and not let Lala get in the way of that.

Rito Yuuki
Rito is one of her closes friends she has, she tries to get him and Haruna together even if it means possesing Haruna's body. In To Love-Ru Darkness she is shown to have some interest's in Rito, it's unknown if she is also having feelings for him.

Mea Kurosaki
While trying to find out more about Mea and her master Nemesis, Oshizu took possetion of her to see if she can find anything importent in side her mind. While inside her she saw Mea's desire to have Rito lick her and memory Mea fighting a buch of people and demanding to if they know where Yami is, she is also seen talking to Nemisis but Oshizu was unable to see her.

Oshizu discovered that deep within Mea's mind is a darkness so deep that it nearly consumed her interly if she had not escaped in time, frightend by what she saw Oshizu has been highly mistrustful of Mea ever since.