Mutsumi Etou is a main character in the yuri visual novelTenshi Tsuki no Shoujo. A stubborn, naive, hot-blooded yet kind and outgoing ghost girl who spent a lot of time in the material world. She thinks it's fun staying as a ghost because she hates studying and homeworks. She uses the feminine pronoun "Atashi" to refer to herself. She was killed in a car accident.
- On a beautiful moonlit night, when she used to look at Kensuke as usual, she first met Death Angel, and thought that she was an Angel, from that moment she used the name "Tenshi-san/Miss Angel" to call her.
- Thought Death Angel came that night to pick up "a cute girl" like herself who was hanging around alone.
- Resolved to be Sayuki Hashido's counselor though she wouldn't say that they're friends, she did her best in finding her name, class 1-C, and her address through the students book given to her by Death Angel, but because she's a ghost whom Sayuki fails to notice her presence, and her voice wouldn't reach her, she accepted to temporarily enter the body of one of the birds' she was petting, while she was trying hardly to deliver her concealment message to Sayuki, she shouted how Kensuke (the boy they had a crush on) is a fool.
- Would curse Sayuki's bullies to death.
- Wished for her voice to reach Sayuki who was alone in the classroom.
- Granting Sayuki's happiness is her aim.
- At the evening Sayuki was rejected, she hugged her in the spiritual realm and was crying sympathetically even when she didn't notice her, because she wanted to comfort her sadness.
- She once described Sayuki as a cute girl while she was planning to tie her together with Kensuke.
- After Sayuki was dumped, she tried to advice her to just forget about him.
- Wished to hug Sayuki in the material world for a few minutes.
- Asked Death Angel if she's working hard for her because she's a cute girl herself.