The Hospital twintail is the murderer.She wants to meet
Ayumu because she thought she had killed him.The first
question the girl ask is ‘do you remember me’ as in do you
remember me,who had killed you?She try to framed Yuu since
Ayumu don ’t know who the killer is.Yuu is too strong for the
hospital girl to fight,so she try to wreck up their relationship
1st.She purposely touch Ayumu ’s forehead to clean his
memory,like Masou shoujo(yes,she is an evil masou shoujo)but
didn;t affect Ayumu because he is a zombie.She kill human to
collect power(soul?) so that she can live eternally young.Behind
the hospital girl are a supposed final boss? that had zombie
power? obtained from Yuu long time ago.
Yuu’s whole body is strong magic medium like her blood can
made vampire ninja(yes,she founded it to protect human) and
she is the one absorb magic? from haruna cause she had some
kind of bond with Ayumu.She also can made what she said
become truth,like making Ayumu into zombie by simply telling
him not to die,means she also can instantly manipulate and kill
by letting people hear her words.That is why she can’t talk and
she also had strong influence to the fate of the people who go
near her,like Ayumu that had been killed right after meeting
her.So,she constantly thinking all was her fault and at the end of
vol.2,she left Ayumu and Ayumu want to bring her back.