A half-human, half-oni high school girl who transferred to Room 4 of Maison de Ayakashi in order to live alone. She yearns to be independent and constantly worries about not being able to communicate with other people properly, one of her reasons for moving. Her SS agent and servant is Soushi, a fox spirit she'd unwittingly saved, although she's not aware of it.
Babies Ever After: The manga ends with Zange having a vision of Ririchiyo and Soushi getting married and having a son. It's implied that their son will be reincarnated!Soushi, who wished to be born as Ririchiyo's son in the reset timeline.
Living Emotional Crutch: She's Soushi's entire reason for living. It's thanks to her that he developed his own personality and emotions.
Lonely Rich Kid: As the atavist of the family, Ririchiyo was virtually casted away from her parents and she couldn't actually relate to anyone in the household, being considered as merely a family treasure. At school, she was bullied by other kids and the people who seemed to be kind to her were far more interested in her social status than Ririchiyo herself.
Shana Clone: A different take on the archetype. She's a rich, childlike fifteen-year-old Type A Tsundere with black Rapunzel Hair and Zettai Ryouiki, but her attitude shows that she hates her rudeness to outsiders and wishes to get along with people.
Sour Outside, Sad Inside: Her condescending and haughty exterior is actually a defense mechanism she developed in order to cope with her lonely family environment and bullying. In the present, her "bad habit" of talking down to people makes it difficult for her to relate to others and she gets really depressed everytime she unintentionally drives people away because of this. She's also the Trope Namer for the Anime Fan Speak term of the trope since Nobara was the one who came up with the word "Tsunshun" - abrasive and then depressed - to describe Ririchiyo.
The Unfavorite: An interesting case of this. Due to her strong youkai blood, Ririchiyo was treated as a family treasure back at home, while her sister was largely ignored by the rest of the household. To compensate, her parents showered her younger sister with love while rejecting Ririchiyo, believing that she didn't need them anyway.
The assigned SS Agent to Ririchiyo and her servant, Soushi is a half-kitsune whom Ririchiyo helped when she was little. Very calm, polite, and gentle to people, he holds a deep devotion towards his master, blindly obeying her and protecting her with his life if the situation calls for it.
Animal Motifs: He's literally part-fox demon, so there's that, but as the title of the series suggests he's also frequently compared to a dog due to his extreme Undying Loyalty to Ririchiyo. When he's in his demon form, he'll even wag his tails when he's happy.
Becoming the Mask: Not entirely, but pretty damn close. Soushi wrote to Ririchiyo under the guise of an idealized version of Kagerou that he made up in his head, because he felt it was his job to make her like her fiance. He eventually realized that in the course of his correspondence that he not only got lost in the role, but also that he'd begun to feel genuine emotion.
Berserk Button: Harm Ririchiyo in any way, and you'll incur his wrath.
Broken Ace: Soushi is good at virtually everything, but his upbringing and subsequent plots to escape his family caused him to develop the personality of someone who will do anything to get what he wants.
Reincarnated!Soushi takes this a step further by being jealous and resentful of the past!Soushi. Essentially, he's jealous of... himself.
Dark and Troubled Past: His family raised him under house arrest from birth, and when it became too much, he learned to appeal to the sympathies of household workers and members in order to manipulate his way to freedom. He eventually ended up in the service of Kagerou and his family until he turned 20, at which point he was freed.
And history repeats itself when he's reincarnated, where he's put under even worse restrictions than before. However, thanks to Ririchiyo setting up precautions, he didn't have to go to the lengths he did in his previous life to escape it.
Dead Person Impersonation: His reincarnation lacks his old memories but that doesn't stop him from trying his darnedest to act like, and take the place of, his former self.
Extreme Doormat: Totally willing to commit suicide for Ririchiyo's sake or if she declares she doesn't need him.
Gender Bender: His shapeshifting allow him to transform into a woman. Reincarnated Soushi, when visiting Ririchiyo during gym class one day, transformed into a girl because he hoped that Ririchiyo would be more comfortable with the company of a female. Naturally, all of the guys in her class are interested.
Generation Xerox: All the Atavist's reincarnations retain most of their former characteristics, but Soushi's notable for almost flawlessly emulating his past self, despite the fact he, unlike most of the others, does not have his past memories. Also, it only took hearing the stories about the previous Ririchiyo and Soushi, and reading the old letters of correspondence between them, for him to fall in love with Ririchiyo again.
Gold Digger: A... somewhat more sympathetic one before he became Kagerou's servant and met Ririchiyo.
Guile Hero: More than willing to manipulate anyone into getting what he wants, including the mistresses and masters that he works under, putting himself in as much control as he can with his relationships.
Heroic Self-Deprecation: Frequently refers to himself as a "lowly servant" or a "dog unworthy of anything", even for something as simple as a "thank-you". Usually Played for Laughs. To a certain extent, he uses this as to manipulate others and/or to gain control of a situation, but he really, truly is not proud of the way he is, and does not see much value in himself at all.
Huge Guy, Tiny Girl: Huge Guy to Ririchiyo's Tiny Girl. She only comes up to the middle of his chest.
I Just Want a Family: He's told Ririchiyo his greatest dream is to have a child and a family someday. Considering his terrible childhood, this is likely so that he can give someone a better life than the one he did, and also because it was something he'd never had.
I Just Want My Beloved to Be Happy: He might a yandere stalker, but to his credit, he's not willing to make assumptions about his relationship with Ririchiyo, and lets her be the one to decide where they stand with each other. When he says he'd do anything for her, he really does mean it.
I Love You Because I Can't Control You: He'd grown fond of Ririchiyo through the letters they exchanged, but his devotion to Ririchiyo was sealed when he realized that the entire time she'd been aware he'd been distant in his writings, and that when he for the first time ever was genuine in a letter, it didn't escape her notice.
I Owe You My Life: To Ririchiyo. It wasn't until after getting to know her through her letters that he began to develop into his own person.
Also, his reincarnated self. Before she died, Ririchiyo asked Kagerou's mother to release Soushi from his house arrest once he reincarnated.
Keigo: Speaks very respectfully under any and all circumstances.
Lolicon: Sorta. He gets called this in-series at one point, but a seven year age difference isn't nearly as bad as some examples. That being said, when he fell in love with her through her letters, she was only around the age of ten. To be fair, no matter what, Ririchiyo would've been corresponding with a boy nearly twice her age, since her actual fiance Kagerou, who she thought she was writing to, was the same age as Soushi.
Love Before First Sight: Kagerou made him write replies to the letters from Ririchiyo. Soushi got to know her rather well throughout her letters and eventually developed genuine feelings for her even though he had never met her before.
Happens again with his reincarnation, as it only took hearing stories about her and reading their old letters for him to fall for her just as hard as he did before.
Megane: Sometimes. The only times he's really seen wearing glasses is when he's relaxing.
Reincarnated Soushi wears glasses all the time, except when he is in his youkai form.
Me's a Crowd: He's been seen using his duplication abilities to help with chores or as part of battle strategy.
Reincarnation Romance: Subverted. Reincarnated Soushi does love reincarnated Ririchiyo, but she rejects him because his past self is the only one she loves.
Relationship Reset Button: His reincarnation doesn't have memories from the past, which, as stated above, throws a monkey wrench into his relationship with Ririchiyo.
Sarcasm-Blind: Despite the fact that one of Ririchiyo's defining characteristics is that she often says the exact opposite of what she means, Soushi tends to take the things she says way too seriously.
Satellite Love Interest: A rare main protagonist example. He has little personality outside of his devotion to Ririchiyo and he declares his entire existence is solely for her sake. Justified since he basically was an Empty Shell before he met Ririchiyo.
Sexual Extortion: It's heavily implied (and made clear in the anime) that one of the things Soushi did to worm his way to freedom from his life-long house arrest was allow the women in higher positions of his extended family use him for sexual favors. Disturbingly, he started doing this in his early teens.
White Hair, Black Heart: Though there does exist goodness in him, his (self-admitted, even) twisted and manipulative personality qualifies him for this trope. Better qualifies for his reincarnation who really does not care about anyone but Ririchiyo.
Yandere: Oh definitely. He's arguably got more self control than most examples, but his obsession with Ririchiyo and desire to protect her can go to very extreme and disproportionate levels very fast. Renshou even calls him this once.
An Ittan-momen (lit. "one bolt of cotton") half-demon with several tattoos on his tanned skin, he is the tenant of Room 3. He's had a brother-sister relationship with Ririchiyo since childhood, which earns him Soushi's trust. His SS Agent is Nobara.
Celibate Hero: He has had many girls confess their love for him, but he always rejects them, because he feels he will have to separate from them anyway, because while he can reincarnate into basically the exact same person again, humans will not.
Character Development: Renshou is much more jaded after 23 years. His change is starkly shown in chapter 35 in which he wanted to run away from Inugami with the other atavists because he was afraid of watching them die all over again. Nobara snaps him out of it.
Cool Old Guy: As the only member of the main cast who didn't die at the end of Chapter 18, Renshou is already 41 (and has grown a beard) by the time we meet him again 23 years later after the youkai raid.
The assigned SS Agent to Renshou, Nobara is a Yuki-onna whose human form depicts her as a young woman wearing glasses. She likes girls and fashion so much so that, in her free time, she looks at adult magazines with beautiful women in them and shares them with Renshou.
Smart People Play Chess: In Episode 7 she's seen teaching Chino to play the Japanese equivalent, Shogi, which some regard as harder to play than chess (though she does lose). She then suggests playing a card game called Hana Fuda which also has some notoriously complex variations.
Token Mini-Moe: Post-Time Skip, for the agent side — she is revealed to have been reborn a year later than Ririchiyo, making her fourteen years old by the time we see her again 23 years after her death.
Tenant of Room 2 and a half-oni, though a different one than Ririchiyo. He's Soushi, Banri, and Zange's former master, and Ririchiyo's fiancÚ. Kagerou is eccentric, straightforward, and narcissistic, calling the other tenants "pigs" or "human toilets". His SS agent is Karuta.
Bratty Half-Pint: He's an adult version of this in the reincarnated timeline, where his levels of obnoxiousness has remained the same, but he's noticeably shorter than he used to be. He claims he'll grow back to his original height, but he's already 20...
Disposable FiancÚ: The fact Kagerou was engaged to Ririchiyo seems to serve no other purpose than being the reason she and Soushi came into contact with each other, since she can't stand him, and he never shows any sort of interest in her that could remotely be considered "romantic" unless it's to get a rise out of either her or Soushi. Not to mention Kagerou didn't waste any time calling Ririchiyo his ex-fiance after she and Soushi got together.
Averted somewhat with his reincarnation who did actually correspond with Ririchiyo via letters while they were growing up, and there are hints he may have come to develop feelings for her this time around. In which case you could argue it became a really Zig-Zagged case of Matchmaker Crush, since in the original timeline he wholeheartedly encouraged Soushi writing the letters.
Embarrassing Cover Up: Kagerou's personality would make just about anyone assume he was being a lazy jerk when he told Soushi to write the letters to Ririchiyo. The truth was that he didn't want to write to her with his horrible handwriting.
Doesn't happen in the reincarnated timeline though, where he does write to her... though apparently in code!
Held Back In School: In the reincarnation timeline, Kagerou had to repeat four years of school. The result is that he's a legal adult still in his freshman year of high school. True to form, he acts way too proud about this.
Hidden Depths: Yes, when it comes to trying to compare everything to S&M he's absolutely ridiculous. But in the moments where you find him seriously analyzing a situation, or a person's character, he can be surprisingly accurate.
Jerk with a Heart of Gold: He calls his closest friends his livestock, okay? However, he's sloooowly showing more signs that he's a good guy underneath the usual jerkassery he has on display. He (eventually) apologized to Ririchiyo for making someone else write the letters to her that should have been from him, and then proceeded to tell her that the one who really wrote them was Soushi. He also folded 1000 paper cranesby himself to wish for Karuta to get better after she was attacked and then trapped in her demon form.
A Man Is Not a Virgin: Apparently averted, hilariously enough. At least in the timeline where everyone's been reincarnated, it gets heavily implied that Mr. Obsessed With S&M's a virgin when Soushi's asked to reveal an "embarrassing secret" about him.
Mythical Motifs: His theme song in the anime, and overall character design (except in his demon form) have elements that are evocative of a classic vampire.
Not So Different: He frequently insists that he and Soushi are "the same", which Ririchiyo vehemently denies. In certain respects though, he's actually not completely wrong.
Apparently they've also got similar facial features.
Odd Friendship: Most of his friendships, and he's the one who makes them odd. Karuta stands out though since of the six (relatively) close relationships he has in the group, she's the only one that we haven't seen him have a childhood connection to.
Older Than He Looks: His reincarnated self is supposed to be 20, but he looks nearly identical to how he did at 14 in his previous life. The fact he's kept a short haircut and isn't as tall as he used to be only adds to it.
Vulgar Humor: His vocabulary is littered with references to various sex and fetish plays and the only gifts he ever seems to get anyone are S&M props. He also constantly refers to people by way of insulting them and he's the most likely to warrant the need for censor bleeps. In the dub they even once chose to have him drop a "fucktard" in lieu of censoring.
Walking Shirtless Scene: Reincarnated!Kagerou shows up once wearing only his cape as a top and very much showing off his bare front.
Walking the Earth: At the end of the series, Kagerou decides to go traveling around the world to search for a new destiny now that the Hyakkiyakou has finally ended, taking Zange and Kuroe with him.
The assigned SS Agent to Kagerou, a Gashadokuro (large skeleton created from those who starved to death) whose human form is a teenage girl with pigtails. Though she appears to be "zoned out" most of the time, she's actually very clever and observant and likes tasty food.
Relationship Reset Button: Like with Soushi and Ririchiyo, Karuta has to build her relationship with Watanuki from the ground up since Watanuki can't remember the past. Unlike the lead characters though, things are going much better on Karuta's end.
She Is All Grown Up: The reincarnated Karuta is already 20 years old — the oldest female in the household — and has let her hair loose (in addition to being bustier) by the time she is seen again, 23 years after she died at the tender age of sixteen.
Token Mini-Moe: For the agent side until her reincarnation, where she is already twenty by the time the series picks up 23 years after she was killed (along with everyone but Renshou) during the youkai raid.
Tenant of Room 1, Banri is a mixed blood Tanuki demon with an impulsive streak and is very outspoken. Labeling himself a "delinquent", he considers Soushi his rival because he called him cute, causing Banri to resent him. His SS agent is Zange.
Adorably Precocious Child: Not so much a child, but his reincarnated self is a junior high school boy, making him the youngest of the reincarnated cast and at least six years younger than the reincarnation of his crush, Karuta, who is now his agent.
Power Incontinence: He doesn't have a very good control over his powers and sometimes spontaneously transforms into his Tanuki form, often in response to an emotional state. He finds this to be mortifying.
The assigned SS agent to Banri, Zange is a half-human, half-hundred-eyed monster who wears a set of black rabbit ears on his head. He is a very cheerful and eccentric individual. He's best friends with Kagerou. He also has a fondness for Soushi and has a tendency to flirt with him and call him "Sou-tan" because of this, though he has given pet names to most of the other characters as well. His youkai blood gives him the power of limited omniscience, and he has a penchant for meddling in the lives of his peers, usually with positive ulterior motives.
This is particularly pronounced when Kagerou turns up "dead" in the reset timeline. Everyone else has a shoulder to lean on for emotional support in the aftermath, but Zange's found dealing with mourning for Kagerou by himself.
Ambiguously Bi: Zange shamelessly hits on Soushi and openly states he'd like to sleep with him... he's also peeked at Ririchiyo's panties to prove a point, and when Watanuki wound up clinging to him out of fear in one incident, Zange thought "this would be better if it were a girl". Huh.
The Anti-Nihilist: Zange shows shades of this. He reveals that he more or less remembers everything in his past lives, and observes that destiny repeats with all of the atavists coming to the same tragic ends over and over again, implying that he tried but failed to make things better. This resulted in his Stepford SmilerBroken Bird personality and his philosophy that the other atavists should just enjoy life while they can.
Chivalrous Pervert: Has elements of one. He's a genuinely a caring and friendly guy and not much of a skirt-chaser, but he seems to like showing off the fact that with his powers he can see, and describe in detail, what kind of underwear Ririchiyo's wearing on a given day.
Cool Big Bro: Self-described this in his introduction chapter. Quirkiness aside, he's actually pretty effective. He switches between this and Team Mom to the group.
Expy: His eyes that are usually shut, trickster personality, innate ability to know more than he lets on, and habit of teasing that he has some sort of secret, make him seem like a more flamboyant but univocally good version of Xellos.
Extra Eyes: His youkai blood gives him these, which he can use to search for information.
Eyepatch After Time Skip: Subverted, as he has always covered his right eye. It's just that he replaced his bandages with a patch.
Eyes Do Not Belong There: His entire body is covered in eyes, presumably a hundred of them, considering that his ancestry is that of a Hyakume, or Hundred-Eyes monster. Understandably, they're usually covered up under layers of clothes.
Fun Personified: He likes playing pranks or making people laugh, and he often gathers everyone to participate in games and activities together. He's also one of the only characters who genuinely enjoys Kagerou's crazy hijinks. Okay, so he's a Stepford Smiler, but he should really get points for trying.
Genre Savvy: A bit. Comes with his "all seeing" powers.
Jerkass Fašade: On the surface, he gives the impression of being a shifty character (and that he enjoys being seen as such). He also tends to do things at the expense of the comfort of his friends. But the reality is he's a really nice guy, and more often than not, what he does is for their benefit in the long run.
Manic Pixie Dream Boy: He's a little like one to everyone in how he tries to encourage interactions, but Watanuki and Ririchiyo in particular.
Motherly Side Plait: His default hairstyle could be considered this, and to a certain extent he fills in the role. Oddly his reincarnated self no longer wears it like this regularly, but it's he who plays up the Team Mom act.
Nice Hat: Trades the bunny ears for one in the timeskip where everyone has been reincarnated.
Non-Action Guy: His powers are definitely useful, but since their primary use is for information gathering and they've proven to put a strain on his health in the process, you have to wonder how he ended up with a job that's supposed to involve being a bodyguard.
No Sense of Personal Space: He isn't afraid of getting into Soushi's personal space or feeling him up, though Soushi never objects to it.
Sharp-Dressed Man: If you ignore the bunny ears. And even more so with his reincarnation who ditched the bunny ears and replaced them with a top hat.
Shipper on Deck: Ships Watanuki/Karuta, if the amount of times his meddling is to get them to have time alone together is any indication. He also seems to support Ririchiyo and Soushi.
Soap Opera Disease: He doesn't have the healthiest disposition. Apparently it's connected to his power.
Stepford Smiler: Is one in general, due to him having to deal with the fact he's got the memories of all his past lives and the horrors and/or tragedies that came along with them. He also tends to distract people with jokes, and/or play things down when he's overworked himself or isn't feeling his best.
Trickster Mentor: Zange often plays pranks and meddles in the lives of the other characters in such a way that people question whether he's a nice guy or not, especially in the cases of Ririchiyo and Watanuki. His actions usually end up helping them with their problems in one way or another.
We Used to Be Friends: Doesn't involve a falling out of any sort, but reincarnated!Watanuki lacks his past memories and didn't grow up with reincarnated!Zange as a "Childhood Friend", so they're practically strangers. They also rarely get to interact with each other since in this life, Zange's not Watanuki's SS Agent, and there are moments where it's painfully obvious that Zange misses their old relationship.
A cheerful maid that works in Maison de Ayakashi who's perpetually happy and performs her job with passion. She has the ancestry of a Koropokkuru, and thus can transform into a really small form, which helps her clean really narrow places.
Another maid who works at the Maison and crossdresses in a French Maid Outfit. His personality is sensible and wry, which contrasts that of the other maid Chino. He has the blood of a zashiki warashi, which gives him the power to bring great fortune to any household he resides in.
The third "maid" working at the Maison. He is a man with a somewhat outdated sense of humor who cheerfully talks about his recent divorce and layoff. His youkai form is an orochi, an eight-headed snake monster.
She is the one responsible for the creation of the Maison de Ayakashi as part of her struggle to gain civil rights for other atavists back when she was younger. Known as the atavist with the strongest spiritual power, she has the ability, similar to that of Zange, of omniscience. Her power is so strong that she must stay cooped up at her family residence away from other people so she doesn't get overwhelmed by information.
Aunt Pennybags: The main characters are a bit taken aback when meeting her for the first time; her personality doesn't really fit her status and wealth.
Big Good: Subverted. She's actually behind the Hyakkiyakou along with Mikoto, wishing to recollect the information from the atavists' corpses and find a way to end the reincarnation cycle.
A mysterious atavist with the ancestry of a dog god, who wants to bring about another Hyakkiyakou, the last of which was connected to the deaths of the main characters 23 years ago. He's the leader of the rogue atavists.
Locked into Strangeness: His hair was originally black, but it turned white after he tried to use the Thousand Year Sakura Tree to go back in time.
Love Makes You Evil: His motivation for causing the Hyakkiyakou is his love for Shimon, who wants to examine the atavists' corpses and search in their memories a way to stop the reincarnation cycle. All he wants is to make his beloved Shimon smile.