Mizushima Miho

Mizushima is a classmate of Takahiro and a part of the residential group. After the attack and fall of the colony, she was attacked by someone who attempted to rape her. She then committed suicide to avoid being raped. Sadly she still had her body violated by the attacker and was then later consumed by Lily who takes her physical appearance.

Relationships
Takahiro - classmate and member of the residential group.

Kato Mana - kouhai from Miho's club and close friend.

Abilities
Cheat ability - little is known about her ability but it's possible she has one because of Takahiro

Appearance
Mizushima is considered to be one of the top five beauties at her school. Her blonde-dyed hair went through a brass hair band, and reached her shoulders. She has a slender body and is said by Takahiro to leave a child-like impression with her.

Personality
She seems to be very sociable and has a gentle personality. Kato has described her as "someone dense about boy's feelings", it's softly implied that she has a nice personality which makes most male students hopelessly fall for her without Miho being aware of it.

Plot
This segment contains MAJOR spoilers for the later volumes

First Arc
Mizushima Miho kills herself as a last resort to prevent being assaulted, she is later consumed by the mimic slime Lily under Takahiro's orders.

After settling the score with Mizushima's attackers, Takahiro "perceives" signs of an incoherent regret inside Lily, never doubting such regret to be coming from Mizushima; it is then that Takahiro does his best to dispel her chagrins.

Third Arc
At the peak of the arc, it's revealed that a large part of Miho's soul has been kept "untouched" inside Lily, this was partly thanks to Lily's own complex feelings on which she believed that she can never become Miho. After Lily came to terms with the soul, Mizushima becomes a single existence with the slime and is able to communicate with Lily; Miho can even help Lily on using her powers in ways that it would be impossible otherwise (such as, mimicking several organisms at the same time).

After becoming one, Miho can sometimes "take the place" of Lily in controlling their body, and sometimes does this to chime into the conversation.

Fourth Arc
Lily learns how to temporarily split herself into two weaker slimes. One of those slimes contains Mizushima's soul and is capable of shifting into her original body; which Miho herself describes as "a second chance in life". Ironically, here it's revealed that Lily and Miho are not identical in appearance and that Miho figure is actually less alluring than Lily's (Mizushima is deeply troubled by this).

This arc actually voiced something that has been hinted previously; Miho has "enjoyed the embrace" of the person she loves even though Miho herself hasn't done anything to advance her own romance (such as confessing and pursing her love). In other words, it's implied that Miho has lived Lily's romance from inside the slime's body, and has come to love Takahiro on her own.

End of Spoiler segment.

Trivia

 * A maiden killing herself as to preserve her purity rather than live in disgrace was a common stereotype of ideal woman in ancient Asian folklore. Most young maidens even carried small knifes for such purpose.
 * Lilies can symbolize that the soul of the departed has received restored innocence after death.