History Characters / HekikaiNoAiON

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

** {{Meido}}: The cafe's uniform.
* FirstNameBasis: With Minato. She also used to have this with Tatsuya, but since everybody thought she was [[{{Golddigger}} taking advantage of him for being rich]] and her allergies kicked in, she's starting to keep her distance.
** They get back to the first-name basis after [[spoiler:the Mushi incident]].

* LikeAnOldMarriedCouple / ShipTease / BelligerentSexualTension: With Minato.
* MissingMom
* MoodSwinger
* MoreThanMindControl: [[spoiler:When she was infected by Mushis,]] they used her jealousy of Seine and her fear that Tatsuya knows she wanted his dog dead to break her will.

* [[YouGottaHaveBlueHair You Gotta Have Purple Hair]]

* {{Bishounen}}

** KeepingSecretsSucks
* DisappearedDad
* {{Expy}}: Of [[Manga/{{Karin}} Ren]].
* {{Foil}}: To Tatsuya.
** BromanticFoil
* LikeAnOldMarriedCouple / ShipTease / BelligerentSexualTension: With Nagisa.
* LongHairedPrettyBoy: After TimeSkip.
* MuggleBestFriend
* PermaStubble: After TimeSkip.

* TallDarkAndHandsome
** TallDarkAndSnarky: To some degree.

* [[YouGottaHaveBlueHair You Gotta Have Green Hair]]

* {{Adorkable}}
* AlliterativeName
* CurtainsMatchTheWindow

** IGotBigger: Though 19-years-old Tatsuya looks quite the same as 16-years-old Tat-chan, just bigger.

* DoggedNiceGuy: To Seine.
** [[spoiler:RelationshipUpgrade[=/=]OfficialCouple]]
* DraggedIntoDrag: Forced to dress up as a {{meido}} as part of his class's cafe staff. And the girls rejoiced.
** AttractiveBentGender: ...but no one can deny he looks so cute as a female.

* HeroicWillpower[=/=]ThePowerOfLove: Why he didn't [[spoiler:kill Seine even after being infected.]]

* [[spoiler:JourneyToTheCenterOfTheMind]]
* LethalChef: As [[IllGirl Shizuki]] [[BloodFromTheMouth discovered]]. Only Seine is not bothered by his cooking.

** KidWithTheLeash: He's also the only one able to control and stop Seine when she's on a rampage. [[spoiler:Also, he could be this to Sheila too.]]

* OneHeadTaller -> HugeGuyTinyGirl: With Seine.
* OrdinaryHighSchoolStudent

** ConvenientlyAnOrphan: Admit it, Tatsuya suddenly filling his house with a bunch of young women will be very awkward if his parent were alive.

** After FirstNameBasis: "SEINE-CHAN!"

* [[spoiler:TogetherInDeath]]: With Seine.

* SugarAndIcePersonality
** Later, she evolved to a {{Tsundere}} towards Tatsuya.

* ActionGirl
* [[spoiler:AdventuresInComaland]]

* BrokenBird: [[spoiler:The first 4 years of her life were horrible, her ParentalSubstitute was killed in front of her and she's seen lots of people she cared about dying as well.]]

* Creator/HarukaTomatsu: Her Drama CD VA.

* IAmAMonster
* IGaveMyWord: When she finds someone who [[PleaseDontLeaveMe asks her to stay by his/her side,]] she stays until they die, tell her to leave, or obstruct her revenge, [[spoiler:because she used to be completely alone, too.]]
* {{Immortality}}
** TheAgeless
** GoodThingYouCanHeal
** ImmortalLifeIsCheap
** ResurrectiveImmortality

* IWorkAlone

* NotSoStoic
* OrdinaryHighSchoolStudent: Subverted.
* ParentalAbandonment: [[spoiler:She doesn't know anything about her biological parents.]]
* PowerTattoo
* PrettyFreeloader
* [[Really700YearsOld Really 300 Years Old]]
* [[spoiler:RelationshipUpgrade[=/=]OfficialCouple]]: With Tatsuya.
** [[spoiler:TogetherInDeath]]

* BadassGrandpa

* CoolOldGuy

* [[spoiler:EatenAlive]]

* PosthumousCharacter
* PowerTattoo
* [[Really700YearsOld Really 1700 Years Old]]
* ScarfOfAssKicking

* [[spoiler:OurGhostsAreDifferent]]

* CovertPervert: She's an "Oyaji-con"; she likes [[GrandPaWhatMassiveHotnessYouHave old, handsome men]]

* GrandPaWhatMassiveHotnessYouHave: Let's face it, for a man who look in his 50-something and actually is 1700 years old, Simon look very good.
** Even Shizuki admited she would totally do him if she could had decided stop his aging a little more lately so he would be older enough of her standard.

* {{Big Bad}}s

** Bikini in the PoolEpisode.

** LightningBruiser

* CombatStilettos

* DumbMuscle
* ExtremeDoormat / TheCaretaker: To her sister.

* ImpossibleHourglassFigure

* InnocentBlueEyes

* TheOjou
* MeaningfulName: Yuzuki means "kind moon".
* {{Meido}}: She works as a maid in Tatsuya's house.
** GiantPoofySleeves
** OfCorsetsSexy
** ZettaiRyouki
*** StockingFillerRinglets

* [[spoiler:PutOnABus]]
** [[spoiler:TheBusCameBack]]: In chapter 40.
* Really700YearsOld
* SupremeChef / TeamChef
* TaremeEyes

* BoundAndGagged: Her own parents did this to her when they were {{brainwashed and crazy}}.

* DissonantSerenity: Since he's [[{{Immortality}} immortal]] and knows [[GoodThingYouCanHeal his wounds can't be fatal]], he's always cheerful even in in the face of danger.

* [[BigBrotherBully Big Sisters Bullies]]: All but Ariel pick on their youngest sister.

* BigBrotherMentor: To Tatsuya; who calls him "Tsukasa-[[JapaneseSiblingTerminology niisan]]".

Yuzuki is Shizuki's younger sister. She is the polar opposite of her sister: she has superhuman strength, is diligent and a good cook, but is a little dumb. She is good-hearted and carries out her Onee-sama's orders. She also has an immortal body and has lived for centuries. She is a Lolicon (she gets excited by children, especially girls) to the point of kissing every child she meets on the mouth (occasionally ''with tongue'') upon first sight.

* ForcefulKiss: The way she expresses her [[{{Lolicon}} love]] for little girls. '''Any''' little girl.

* {{Lolicon}}: PlayedForLaughs and LesYay.

* MamikoNoto: His Drama CD VA.
** CrossdressingVoices

* TomboyishSidetails

* DissonantSerenity: Since he's {{Immortal}} and knows [[GoodThingYouCanHeal his wounds can't be fatal]], he's always cheerful even in in the face of danger.

* {{Expy}}: Of Maki from {{Karin}}. They have a similar appearance to each other and are childhood friends to the main character. Nagisa's BelligerentSexualTension with Minato also parallels to Maki and Yuuji's SlapSlapKiss relationship.

* {{Expy}}: Of [[{{Karin}} Ren]].

* {{Expy}}: Of {{Karin}}, though only in appearance.

Tatsuya's little first cousin.

* WaterWorks: He cries a lot.

* HarukaTomatsu: Her Drama CD VA.

* NiceGuy: Initially.
** TheMessiah: He evolved to this, [[spoiler:he stopped Seine from 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!?

* HeroicSelfDeprecation: She thinks she's a bad, selfish person, unworthy of TheMessiah Tatsuya. She gets better.

* EvilEye: While using Aion.

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

* HazelEyes

* WhiteHairedPrettyGirl / ShyBlueHairedGirl

* BigBreastsBigDeal: Type 5

* BadassLongHair

* ExpositoryHairstyleChange: After the TimeSkip, she's seen with a BobHaircut instead of her long side ponytail.

* ObliviousToLove

* ControlFreak: Mild example. Since she is in charge or her house, she's very strict even with her [[BumblingDad father]]
* DamselInDistress: When she was infected by Mushis.

* PlotAllergy: She's allergic to dog hair.

Miyazaki Seine is a 300 year old girl with an immortal body who Tatsuya invites to live in his home; before that she lived in a cardboard box in a park. In the first chapter, Seine looks like a masochist because she seems to like being bullied. Actually, she becomes close to people who are infected by "mushis", a kind of parasitic, mind-controlling bugs, in order to hunt them. Her hunting ways go against the kind and pacifist Tatsuya's beliefs. Her motive is to avenge her foster father, Simon's death by killing the people of sea, the mermaids. She controls a black snake called Aion that lives inside her. Her weakness is her inability to swim.

* HeroicSelfDeprecation: She thinks she's a bad, selfish person, unworthy of {{messiah}} Tatsuya. She gets better.