(chronologically 19 after the time skip)
|School||Mihama Middle school
(Namiji before it closed down)
|Relatives||Akari Sakishima (older sister)|
Tomori Sakishima (father)
Akira Shiotome (nephew)
Itaru Shiotome (brother in law)
Miuna Shiodome (adopted niece)
|Manga Debut||Chapter 1|
|Anime Debut||Episode 1|
|Japanese Voice||Natsuki Hanae|
|English Voice||Max Mittelman|
Hikari Sakishima (先岛光 ) is the childhood friend of Manaka Mukaido who looks after her and has been doing so since the two of them were young.
One of four childhood friends from Shioshishio. He has a short temper and usually scolds Manaka for her mistakes though he has deep feelings for her. He is the son of Shioshishio's Chief Priest who serves the Sea King. By tradition, this makes him the future Chief Priest. At first, he hates all people from the surface but after learning about the relationships between the land and sea humans (through Akari and Itaru), he gradually understands that there is no difference between the people from the surface and the sea. He goes into hibernation shortly after saving Akari during the Ofunehiki festival. After the 5-year time skip, Hikari reappears during a Tomoebi without any signs of aging. He rejoins Mihama Middle School as Miuna and Sayu's classmate and lives in the Shiodome home with his sister. In the last scene, Manaka's and Hikari's feelings are clear to be mutual.
Hikari is regularly seen in the blue and white uniform of his original school, Nami Junior High, from beneath the sea which was closed down. Like all people from the sea, Hikari has deep blue eyes which is the colour of the ocean while his hair is brown. After his hibernation, he is seen wearing his school's uniform at school and casually wears a blue hoodie and a pair of shorts. As well as his new Mihama Middle School uniform.
At first, Hikari looked down upon people from the surface, viewing them as inferiors who threw away what the sea king gave them in exchange for their own greed. As seen with Manaka, he has a great deal of pride for his life in the sea. He is short-tempered, aggressive, energetic, and impulsive, but fiercely loyal. He's also very determined when it comes to Manaka.
However, Hikari soon matures and comes to terms with people from above the sea, soon acknowledging that they aren't different and starts to wish they could work together.
When he was young, Hikari's mother passed away. Distraught by this loss, Hikari openly wept at her to wake up while being comforted by his older sister Akari. Their father has been taking care of them on his own.
Years later, Hikari was told by his sister Akari that she would be working on the surface. Being against it, he was told that their family needed the money so he could go to college, and although he claimed he would not go, he soon dropped the argument when his sister began crying.
Rushing out of his house for his first day of school above the surface, Hikari passes his friends as he spots Manaka wearing the uniform of their new school rather than their old. Scolding her for attempting to please the surface dwellers, Hikari is told to stop by Chisaki but manages to get Manaka to go home and change. Leaving to go to school with Chisaki and Kaname, Hikari waits at the exit of the ocean for Manaka but she does not show up. Waiting longer, he is surprised to find that she had been caught by the net of a fishing trawler.
At school, Hikari takes part in introductions but quickly gets irritated as the surface dwellers make fun of him and his friends for being from the sea. Arguing and insulting them back, Hikari attempts to get Manaka to do so as well but is unable to as Chisaki stops him once again. During P.E Manaka races Tsumugu Kihara, whose grandfather fished up Manaka that morning. While running, Hikari loses his balance and falls onto Tsumugu, taking both of them down.
Later that day, Hikari meets Akari on his way home and discusses her recent vandal problem. Upon returning underwater, Hikari is spoken to by a mens club who are angry with the surface dwellers recent actions against them. As he recalls the history of people and their origins, he takes his leave and meets with Manaka. Visiting Lord Uroko at the shrine, Hikari witnesses him approach Manaka, causing her to cry and run away and he to curse her as a result.
The next morning, Hikari and his friends head to Manaka's house to pick her up but find that she is refusing to leave. Heading to her bedroom alone, Hikari asks her what the problem is and finds that her kneecap has become a fish head. Knowing that this was the curse Lord Uroko used, Hikari gets angry but quickly sets it aside. As she continues to refuse to go, hoping nobody will see it, Hikari eventually convinces her to go by covering the head up.
However, Hikari comes to find out that Manaka ran away from school and goes out to look for her with Chisaki and Kaname. Despite their efforts, they are unable to locate her and forced to return to the water due to their skin cracking. However, Hikari later resumes the search and finds Manaka alongside Tsumugu, whom he attacks. After being pulled off by Manaka, Hikari laments her apparent closeness with Tsumugu as the two of them return home.
Manaka is one of Hikari's childhood friends. Hikari has always had feelings for Manaka and he would do anything to make her happy, which is the reason why he scolds her a lot in the beginning. He gets very jealous when Manaka is around Tsumugu, but after he learned about the relationship of the land and sea people, he decides to support Manaka and her feelings for Tsumugu.
After the timeskip, he searches for Manaka with Kaname's and Miuna's help and successfully finds Manaka in an Ojoshi-sama graveyard. Hikari promises he'll never let go of her after she wakes up because he doesn't want what happened at the Ofunehiki to happen again. But, after she wakes up a week after they find her, he finds something fishy about her. When Hikari asks Manaka to tell him the thing she wanted to tell him after the Ofunehiki, he realizes that she had forgotten all her memories of love and now where her love is a big hole screaming it's lonely. Thus she is never able to confess her feelings for Hikari after the Ofunehiki, and never being able to love him again. But, Hikari believes that she was in love with Tsumugu and not him seeing that she rejected him after he confessed his feeling for her. Even though he thinks that, Hikari thinks more about Manaka more than his own feelings about her. He wants her to remember what it feels to like someone and have happiness once again. After they decide to do the Ofunehiki to gain Manaka's feelings back, he tells her she will gain back her memories of love back no matter what. It is soon revealed that Manaka is in love with Hikari and that their love wasn't one-sided. Manaka tells Tsumugu that Hikari is like the sea, always protecting her. At the final scene the two walk on the beach. Hikari and Manaka watch the sea together, now certain of their feelings for each other.
Chisaki is one of Hikari's childhood friends.The two were always together with Kaname and Manaka when they were in junior high. Chisaki is known to have had a crush on Hikari but Hikari was already in love with Manaka.
Kaname is one of Hikari's childhood friends and best friend. The two were always together with Chisaki and Manaka when they were in junior high.
At first Hikari hated Tsumugu because he was the person that Manaka seemed to have feelings for. But after he realized that Tsumugu is a nice guy, he decides to support Manaka and starts to be friends with him. Tsumugu also loves Manaka's fish that was on her knee. That's why he would always ask if it was okay. He also start's to develop feelings for Chisaki. While Hikari tries to tell Kihara to go out with Manaka Kihara tell's Hikari that he loves Chisaki. Chisaki overheard what he said and ran into the ocean. Kihara ran after her while he got ena because of the ena he got from his dad
Miuna is Hikari's step-niece. Even though Miuna is Hikari's niece, Miuna has a crush on Hikari. You can see little bit's of her jealousy through out the show. But, Hikari only thinks that Miuna's feelings for him is because they are family. Miuna doesn't want Hikari to ever know that she is in love with him. She knows she'll never change Hikari's heart that is in love with Manaka and tries to forget it with pain. She becomes the sacrifice in order to save Manaka and remembers that she is in love with Hikari as she falls asleep. In truth, Hikari only thinks of her as a little sister and he is a big brother that needs to show brotherly love to Miuna.
Akari is Hikari's older sister. When they were little, Hikari used to called Akari "Onee-chan", but after the death of their mother, Hikari started to called Akari by her name because when their mother died, Akari did not cry. But after he supported her loved for Itaru, Hikari started to call her "Onee-chan" again.
Tomori is Hikari's father. Hikari hated his father because Tomori declined to have the Ofunehiki and didn't support Akari's love for Itaru. However, their relationship is mended later on in the series after Tomori becomes more accustomed to Akari and Itaru's relationship and marriage.
Akira is Hikari's nephew. The two enjoy playing kanco with each other. Akari says that when Hikari was young, he looked exactly like Akira, but Hikari wants his father's opinion when he awakens.
Itaru is Hikari's brother in law. At first, Hikari never forgave Itaru for dating Akari because he was from the surface. But after learning about their relationship, Hikari comes to understand that there's no difference between the people from the sea and those from the surface.