History Characters / HekikaiNoAiOn

* ThirdPersonPerson: She grows out of this after [[spoiler:the Mushi incident with her parents]].

* ImposibleHourglassFigure

* ImposibleHourglassFigure

* ParentalAbandonment: His parents died a week before the start of the history

* OlderThanHeLooks: He looks like in his early 20, but it's 27. After TimeSkip, he looks practically the same but now is ''31''.

* [[spoiler:[[GodInHumanForm Goddess in Human Form]]]]

* [[spoiler:[[GodInHumanForm Goddess in Human Form]]]]

* VitriolicBestBuds / ShipTease / BelligerentSexualTension: with Minato.

* VitriolicBestBuds / ShipTease / BelligerentSexualTension: with Nagisa.

* WiseBeyondHerYears: She's the most dependable one in [[spoiler:Tatsuya's house]].
--> '''Minagi:''' With the [[HilariouslyAbusiveChildhood kind of parents I grow up with]], you have to grow to be dependable you want it or not.

** ShooTheDog

* HairColorDissonance: Is she a brunette or a dirt blonde?

* ImportantHaircut

* ShowingTheForehead

* TheDitz: Anshu.

* BerserkerTears / BrokenTears: Cried this while [[spoiler:[[BrainwashedAndCrazy choking Seine to death]].

* ImmortalLifeIsCheap: / GoodThingYouCanHeal

* MoralityPet: To her sister [[spoiler:Ariel]]

* AnimalEyeSpy: Shizuki can see through the eyes of Chibi Piyo-piyo. [[spoiler: and since Croquet eat Chibi Piyo-piyo, she can see what Croquette sees.]]

** [[spoiler:Also, her ex name. "Pistis Sophia" is the female divinity of gnosticism that means "Faithful Wisdom"]].

** AttractiveBentGender: ...but no one can't denied he looks so cute as a female.

* {{Pettanko}}

* HollywoodPudgy: She apparently consideres herself fat and she had taken summer diets that ultimately fail.

* TheWoobie: All her sister but Ariel are total {{Jerkass}} towards her

* AbusiveParents: [[spoiler: Her second father]]

* [[spoiler: AdventuresInComaland]]

* BrokenBird: [[spoiler: The first 4 years of her life were horrible, her ParentalSubstitute was killed in front of her and she had seem lots of people she cared about dying at their time]]

* IGaveMyWord: When she found someone who [[PleaseDontLeaveMe ask her to stay by his/her side,]] she stays until the last day [[spoiler: because she was once the same as them.]]

* ParentalAbandonment: [[spoiler: She doesn't know anything about her biological parents]]

* TheBigDamnKiss: [[spoiler: Finally the guy gather courage and give one to Seine in chapter 39]].

* [[spoiler: JourneyToTheCenterOfTheMind]]

* LivingEmotionalCrutch: He became more or less this to Seine after [[spoiler: his JourneyToTheCenterOfTheMind of Seine and learning why she's so broken]]. He promesed her to always be there for her and, as a bonus, he reminds her of a past friend.
** KidWithTheLeash: He's also the only one able to control and stop Seine when she's in a rampage rage. [[spoiler: Also, he could be this to Sheila too.]]

** TheMessiah: He evolved to this, [[spoiler: he stopped Seine of killing Sheila and convinced Sheila to desist in her revenge]] but...
*** StupidGood: Seriously Tatsuya [[spoiler: Who in their sane mind puts a mermaid to live under the same roof as Seine]] just because you like them both!?

* DamselInDistress: [[spoiler: when she was infected by Mushis]]

** They get back to the first name basis after [[spoiler: the Mushi incident]]

* MoreThanMindControl: [[spoiler: When she was infected by Mushis]] they use her jealousy to Seine and her fear that Tatsuya knows she wanted his dog dead to break her will

* BoundAndGagged: [[spoiler: For her own parents, when they were {{brainwashed and crazy}}]].

* HairColorDissonance: Is she a brunette or a dirt blonde?

* OutOfFocus: {{Lampshaded}} in chapter 25. [[spoiler: This may change now that she lives in Tatsuya's house]].

* SpoiledBrat: She grows out of it after [[spoiler: the Mushi incident with her parents]].

* ThirdPersonPerson: She grows out of this after [[spoiler: the Mushi incident with her parents]].

* WiseBeyondHerYears: She's the most dependable one in [[spoiler: Tatsuya's house]].

* TeamChef: After TimeSkip. He became this after moving to Tatsuya's house [[spoiler: since Yuzuki was PutOnABus along with Shizuki]].

* [[spoiler: [[GodInHumanForm Goddess in Human Form]]]]

* [[spoiler: PutOnABus]]
** [[spoiler: TheBusCameBack]]: in chapter 40.

* [[spoiler: [[GodInHumanForm Goddess in Human Form]]]]

* [[spoiler: PutOnABus]]
** [[spoiler: TheBusCameBack]]: in chapter 40.

She was introduced as a new transfer student; and Tatsuya is given the assignment of teaching her sign language. [[spoiler: The youngest of the mermaids; she is despised by all her older sisters except for Ariel. Seine thought she had killed her some 300 years before, but Ariel restored her body almost entirely, leaving her badly scarred about the neck and unable to talk, but with the ability to change herself to have legs and walk about on land. Her true goal is infect a lot of people to order to take revenge on Seine for leaving her without her voice.]] She falls in love with Tatsuya.

[[TimeSkip Four years later]] she stills meets Tatsuya as he promeses her [[spoiler: for stop thinking of avenge herself]] but [[spoiler: she's discovered by two of her sisters and leaves the sea in fear. Tatsuya took her into his house even though Seine is there; Seine allows she lives there but as a host against her sisters]]. She seems very jealous of Seine for being target of Tatsuya's affections.

* [[spoiler: AntiVillain: [[SlidingScaleOfAntiVillains Type 2]] ]]
** After 4 years, [[spoiler: she evolved to [[SlidingScaleOfAntiVillains Type 4]]]] since she still hate Seine.

* [[spoiler: BackFromTheDead]]
** [[spoiler: CameBackWrong]]
* BecauseYouWereNiceToMe: She ordened [[spoiler: to the infected humans]] to [[YouWillBeSpared do not hurt Tatsuya]] because he was nice to her.

* FishOutOfWater: [[spoiler: Quite literally; since she starts living in Tatsuya's house]]
* ForcefulKiss: [[spoiler: The way she infects humans at land]]
** [[spoiler: At the end of chapter 38, she gives one of this to Tatsuya.]]
* GirlinessUpgrade: After becoming a new [[spoiler: PrettyFreeloader]], Nagisa put her intro a cute dress.

* HeroicRROD: [[spoiler: If she overstay at land, Sheila's body will start to painfully rot, because her body is a human corpse from neck down. She just can live safe in the sea]]

* SchoolUniformsAreTheNewBlack: Sheila is always showed wearing her uniform [[spoiler: Justified; it seems to be her [[LimitedWardrobe only wardrobe]]]]

* [[spoiler: UnusualEars: As a mermaid]]

Simon was Seine's third foster father and the one person who showed her kindness when she was young. He was known as a magician in his time and was also known to be 1700 years old (about 300 years ago in present time of the story). He bore the "Aion" mark, just like Seine does at the present time, but he had it across the right shoulder, and was able to use Aion's power for his own, unknown, reasons. [[spoiler: He died eaten by the mermaids]]

* [[spoiler: EatenAlive]]

They are Seine's prey, in revenge of Simon. In-universe, they are the ones who sank Atlantis and Mu, destroyed Pompeii, Italy and sank Port Royal, Jamaica in orden to collect psyche from humans. Until now, 5 of the 7 mermaids had being introduced. They are Ariel the eldest, Bella the second, Enati the third, Anshu the forth and [[spoiler: Sheila the seventh]].

* AsskickingEqualsAuthority: No matter if you're younger, if you're powerful enough you can take your older sister's place in the ladder. [[spoiler: That precisely is Enati's plan]]

* BadWithTheBone: Enati [[spoiler: uses Simon's skull to make an illusion of him]].

* BreakThemByTalking: Enati and Anshu to [[spoiler: Sheila]].

* CollectorOfTheStrange: Anshu likes to collect [[spoiler: human parts]].

* [[IHaveNoSon I Have No Sister]]: Bella to [[spoiler: Sheila]].
* LotusEaterMachine: [[spoiler: Ariel put Seine in one of this]].