14 (After time skip)
|Height||135cm (at 9 years old)
158cm (at 14 years old)
|School||Hama Elementary School
Mihama Middle school
|Relatives||Itaru Shiotome (father)|
Miori Shiotome (birth mother) (deceased)
Akari Sakishima (step-mother)
Akira Shiotome (half-brother)
Hikari Sakishima (step-uncle)
Tomori Sakishima (step-grandfather)
|Manga Debut||Chapter 1|
|Anime Debut||Episode 1|
|Japanese Voice||Mikako Komatsu|
|English Voice||Xanthe Huynh|
A third grade elementary school girl who is Itaru's daughter. Miuna met Akari when she visited them shortly after she was born. She loves Akari but the thought of losing her like she did her mother caused her to refuse to accept Akari as family. Later on, she overcomes her fear and fully accepts Akari as her new mother. She has a crush on Hikari. During the five year period of the time skip, Miuna could usually be found staring out at the ocean waiting for Hikari to return. After the time skip, she enters middle school with Sayu. Her feelings for Hikari have only grown stronger, even to the point of rejecting one of her other classmates who has liked her since elementary school. When Miuna falls into the sea by accident, she develops Ena on her skin which allows her to breathe underwater like her mother. In episode 25, she becomes the Ojoshi-sama but is later saved by Hikari
Miuna has straight black hair inherited from her biological mother. She has light blue eyes as her mother was from the sea. After the timeskip, Miuna is often seen wearing her Mihama Middle School uniform. She grows her hair out very long and ties it up in ponytails around the sides of her head.
Miuna is very shy and often relies on her best friend, Sayu to do the talking. She isn't very direct about her feelings, often using gum to write them on a wall instead of telling them verbally, as a 9-year old. After the timeskip, she is a bit insecure but now is a smart, kind, bold, and independent young middle schooler. Miuna cares very much for her mother even though she and her best friend Sayu were shooing Akari away.
Miuna's mother passed away while she was young, which led to her fear of losing people close to her again. Her mother was from the sea originally, but was unable to go back after she chose to stay on the surface and marry Miuna's dad.
Miuna first met Akari soon after she was born, because she was close friends with her mother. Miuna loves Akari, however after Akari and Itaru tells Miuna that they want to get married, she begins to worry that she would lose her too like she lost her mother. Miuna tries to reject Akari and writes "Go Away" with gum on the walls of the store that Akari works at.Eventually Akari decides that she is hurting Miuna by replacing her old mom, so she decides to leave Miuna alone even though she loves her a lot. Miuna then runs away, but Hikari and the others all find her by the piers. Miuna loves the sea because her mom was from it, so she jumps into the water wishing that she could swim in the ocean like her mother could. Hikari jumps in to save her and after they surface she tells him about how she doesn't want to lose another mommy. Hikari tells her about all the people he likes, including Miuna now. The following day when Akari finds the two of them, she starts to cry and tells Miuna that while she can't replace her old mom she doesn't ever want to leave her.
Miuna develops a crush for Hikari, and later worries about the idea of Hikari going into hibernation. She and Sayu feel that they are "evil" because they would rather Hikari and Kaname stay on the surface than go into hibernation where they can be safe. Miuna also worries about Akari, wishing that she too would go to sleep so that she can stay safe. Akari rejects the idea, wanting to stay on the surface with Miuna and Itaru no matter what.
After the time skip, 5 years passes and Miuna often thinks about the sea where Hikari is. She wishes that she could see him again. Miuna is now 14 years old, and goes to the same Junior High School that Hikari went to before. After Hikari wakes up and comes back, Miuna is excited that he's back and that they're now the same age, but she sees that Hikari is still in love with Manaka. She is also told by several people that Hikari is her uncle-in-law and that they can't be together, regardless Miuna still has feelings for Hikari.
While at the pier with Hikari again like when they were younger, a large crane collapses and causes Miuna to fall into the ocean. As she sinks deeper, she suddenly realizes that she can breath underwater somehow. She comes up with Hikari ecstatic and wanting to tell Akari about it.
The next day, Miuna learned that she has ena in her skin. She was so excited to hear that she has ena, because she can show Hikari that they are the alike. The next morning Miuna, Hikari, and Kaname go underwater to find the Shioshishio, following a mysterious sound.
Though Hikari is Miuna's step-uncle, she has feelings for him. She is in love with Hikari, but he can not reciprocate his feelings for her, since he likes Manaka. She does everything she can so that Manaka can get her feelings back for Hikari. She soon becomes the sacrifice in order for them to be together. Miuna doesn't want Hikari to ever find out her feelings for him and tries to forget about them with pain from hearing him say he loves Manaka over and over. But after being the sacrifice, she tells herself that she loves Hikari and falls asleep.
Sayu is Miuna's best friend. The two have been friends every since second grade when Sayu realizes that she wanted to be dear to Miuna, since she was bullied. Sayu cares for Miuna as her friend and will do anything to make her smile. The two would fight once in a while about love, but will make up eventually because the two can never break their friendship.
After the timeskip, Miuna is the only one with mixed feelings about Manaka. At first, she wanted Manaka to wake up when they found her, but she soon realizes that she doesn't want her to wake up. But after getting close, she helps Manaka get back her feelings for Hikari and soon becomes the sacrifice to save her.