The protagonist and resident Chick Magnet. An ordinary, shy teenage boy who's deeply in love with his long term crush Sairenji Haruna, but has the worst luck when it comes to love much less telling her how he feels about her. After sulking in his bathtub one night, a sexy naked pink-haired girl emerges from his tub. Turns out that said girl — Lala — is an extraterrestrial royal princess from the faraway planet of Deviluke looking for an excuse not to go home, setting off Rito's daily routine of trouble and unintentional perversions which get more and more ridiculous as the series progresses.
Accidental Pervert: Quite possibly a contender for Trope Codifier. In fact, the next time you read the manga or watch the anime, take a shot every time he gets into an "accident" with any girl, and kiss your liver goodbye.
Several characters such as Nana even lampshade his piss poor luck when it comes to over the top ecchi scenarios. Momo calls his falling (on the girls) a god-like skill.
Allergic to Love: Even touching a girl's "parts", just thinking about Haruna in a swimsuit or seeing a naked girl will freak the hell out of him and send him running away. He gets a lot better as time goes on, but is still liable to freak out if it goes too far.
Anchored Ship: He's well aware of Lala's affections for him (as well as his own to her) and the possibility of the hots the other girls have for him (thanks to Momo), but decides not to act on any of it in the meantime until he is finally able to confess to Haruna. This causes quite a bit of stress for him.
Aroused by Their Voice: When a phone is broken and repaired/enhanced by Lala it has the side effect of enhancing his voice so that anyone talking to him on the phone a sensation akin to being fondled and caressed. Yui ends up enduring an entire conversation with him leaving her in post-orgasmic afterglow unable to move or talk. Momo collapses in a heap after one sentence.
The Beard: Lala initially uses him as a fake fiancÚ, but when he tells her she shouldn't marry someone she doesn't love (him) she takes it as him understanding her situation of constant marriage meetings and falls for him for real.
Beware the Nice Ones: While the manga has less emphasis on this, give Rito a good reason and he will hit you. This was first displayed when Ghi Bree kidnaps and starts molesting Haruna, and Rito attacks him outright. He's shown no hesitation in fighting Ren when the latter attacks him or does something else that pisses him off, and on several occasions yells at girls that give him grief.
At the end of the original manga, Rito finally has the guts to confess to Lala his true feelings for her and she encourages he do the same to Haruna. Just as he's about to confess to the girl of his dreams, Oshizu accidentally undoes Haruna's top from afar causing her to run away in embarrassment. Having come this far, Rito goes ahead and shouts the three magic words to a group of girls who like him to varying degrees.
Chick Magnet: For a dork who couldn't confess to the girl he crushed on day in and day out, having a sexy alien princess come into his life has done wonders for Rito in more ways than one. Even if some of the girls are way too much for him.
Forgotten First Meeting: Oblivious to the fact that he and Yui, who has just recently remembered, met many years ago.
Gender Bender: Happens five times, all thanks to Lala. Complete with the alias "Riko".
Hates Being Touched: Hates it when girls start clinging onto him. This is more due to embarrassment than anything else. Lately, though, he starts to improve, and even stood up for Run when Yui chastised her for clinging to him.
This also extends to the times when he's a she for the rest of the chapter/episode.
Heavy Sleeper: Stated to be "wild" when he's asleep according to Momo.
Hot-Blooded: Despite being a normal human, he's more than ready to dive headfirst into the line of fire to protect the girls around him.
Male Frontal Nudity: Hits Yami with this. Since he immediately falls unconscious, rather that getting beaten up, she re-dresses him, and tries to pretend that nothing happened.
Nice Guy: A veritable saint for not snapping/forcing himself onto one of the (many) hot girls after all this sexy extraterrestial insanity.
At least several of the girls (Momo and Run at the bare minimum) would have absolutely no problem with Rito "forcing himself" upon them. That's not to say he HASN'T given the idea of having sex with one of the many beautiful girls who like him a thought or two. What he says to Yui in Chapter 4 of Darkness after she says she doesn't mind if he does "shameless things" to her and only her (although she tries to pass said words off as a joke) pretty much implies this.
The So-Called Coward: Rito didn't hesistate to rush in to fight this guy◊ to protect Haruna and Lala. Sure, Ghi Bree turns out to be a frail weakling with powers of Voluntary Shapeshifting that made him look like a roid-raging demon, but nobody told him about that.
Sweet Tooth: At least twice while he was talking in his sleep, usually whenever unconsciously feeling up the latest girl who sneaks into his bed.
Unlucky Everydude: Has trouble confessing his love to Haruna, then after Lala comes along, he seems unable to go through a day without being an Accidental Pervert and chastised by any girl he happens to fall on.
Unwanted Harem: Should he successfully obtain everyone in it as Momo intends, he's going to have a lot of descendants.
The original subject of Rito's affections (and sometimes perverted fantasies), Haruna is the sweet, kind Girl Next Door of their class. As it turns out, she, too, has unspoken feelings for the boy. When Lala came into their lives, instead of a simmering love triangle she quickly became friends with Lala, and even admits to her that she also loves Rito, a feeling Lala encourages.
A-Cup Angst: Played with — she's got quite a decent chest, but when the idea that Rito likes girls with big breasts gets planted into her head, she starts getting more depressed and self-conscious. Only after remembering a speech by Rito about how True Beauty Is on the Inside while comforting Nana (herself suffering from a twice-in-magnitude, justifiable case of this) does she snap out of it and regains confidence in herself.
Demoted to Extra: Haruna began declining in appearances for quite awhile as Yui was slowly overtaking her spotlight. Understandable, considering the fact the woman she was based on — Yabuki's wife — was the source of his Creator Breakdown that eventually resulted in the cancellation of the original series.
Head of Sainan High School's Public Morals Committee, Yui is seemingly obsessed with everything being proper and decent. Much to her displeasure, most of Rito's troubles has dragged her along with him. Thanks to spending time with him, Yui admits she can't deny she has some affection for Rito, but develops an exceptional case of "Cannot Spit It Out".
The Chew Toy: Just how many times now has this poor girl been involved in one of Rito's perverted "accidents"?
Control Freak: An extreme example. One chapter sees her giving demerits for every wrong doing of her classmates. Said issues even extend to her house where she hounds her older brother to put a shirt on when he's shirtless.
Defrosting Ice Queen: She initially acts bitchy to both Rito and Lala. Over time, she loosens up a bit and even picks on Rito when he has one of his classic "accidents". This ultimately culminates in Chapter 4 of Darkness where she finds herself in Rito's room laying on his bed wearing nothing but a button up shirt confiding to Rito that she finally understands that basically boys will be boys even if they do perverted things. She even says she doesn't mind if Rito would like to do "shameless things" with her as long as it's only her. Yui then tries to pass off what she said as a joke and even claims it was all a test afterwards when Rito fumbles for the right response.
He is Not My Boyfriend: Almost completely in denial about her feelings for Rito, even unto herself — more so when she makes him chocolate for Valentine's, all the while insisting that it's just "obligatory chocolate", and after imagining herself becoming married to Rito and eventually pregnant. Right, Yui, you just keep saying that to yourself...
If It's You, It's Okay: What she says to Rito in Chapter 4 of Darkness. In typical Tsundere fashion, Yui tries to deny being serious about what she said...
Kindhearted Cat Lover: Only short of owning one. She even goes to window-shop to pet stores and a lot of her belongings are cat-themed, including a meowing ringtone set to (you guessed it) Rito's number.
Not So Different: With Rito of all people when it comes to relationship woes minus the over the top ecchi scenarios.
Sainan High's queen bee who considers Lala her rival. Of course, her numerous attempts at showing Lala up just made her embarrass herself in the end. She has a crush on Zastin, and is dismayed to learn that he's Lala's servant.
Jerk with a Heart of Gold: While having an arrogant attitude most of the time, Saki has been shown to deeply care about those who are close to her, and throw parties or get togethers which she invites the rest of the cast to on numerous occasions.
Rito's younger, more level-headed sister, Mikan's way too mature for an eleven-year-old (later twelve), having learned to take care of herself at a young age and reportedly has hordes of admirers. That being said, accusations are leveled against Mikan by her own friends and peers as to where her true affections lie.
Only Sane Man: It's a worrying state of affairs when one of the most mature, down-to-earth kids in town is a little girl who has yet to hit puberty. Partially downplayed come Darkness, though, where puberty does hit her hard emotionally.
Haruna and Lala's classmates and good friends, Mio and Risa are a pair of inseparable friends. Both are more than willing to help their classmates with their personal problems ranging from beauty to smarts, but aren't above doing perverted things to them.
Bi the Way: Risa is all but confirmed to be either full blown bisexual, situationally bi, or merely bi-curious. Mio might be in the same boat as well since she too has no problem squeezing other girls boobs just for the heck of it!
Supporting the theory that Risa in particular might go both ways is that she's not only attracted to Rito in general, (though she could just be teasing him) but the latter's female counterpart has definitely not gone unnoticed (nor untouched for that matter) by Risa.
In an extra chapter of Darkness, Momo hangs out with Risa during the weekend and ends up showering at her place after getting covered in both drink and food curtousy of Run and Kyuoko running away from the perverted principal of Sainan High. While in the middle of her shower, a naked Risa barges in and offers to help clean Momo's back which quickly devolves into the former appearing to have her way with the latter. Geez, it sure looks like Risa knew what she was doing huh?
Good Bad Girl: Risa is somewhat implied not to be a virgin, and seems to really know what she is doing when trying to get Rito to have sex with her... All said and done, that fact doesn't stop her from being a bright and good-natured girl who cares about and looks out for her friends.
Skinship Grope: Both are just too happy to "feel up" other girls, but Risa does it the most out of the two.
The Tease: Until Momo appears, Risa was the official user of this trope for the series. One particularly memorable scene has the girls discussing beauty tips. When Risa asks Rito for his opinion, he states that True Beauty Is on the Inside. Risa responds with this. In another instance, she teases Momo while in the shower, causing her to freak out and bail. She regrets overdoing it, but cheekily notes how similar Momo's reaction was to Rito's.
A 400-year-old ghost wandering an abandoned school building, Oshizu was mistaken to have been haunting the place (in reality, it was extraterrestrials trying to find a place to live). From then on, she moves freely around the school campus; in addition, Mikado-sensei creates her an artificial body (with the same face and hairstyle as her original form) for her to inhabit. Oshizu begins working as an assistant nurse to pay off the expenses for her new body.
Cute Ghost Girl: Initially. She gets an artificial body later on, but she is still basically just possessing that body.
Fish Out of Temporal Water: Having remained within the old school building for four centuries, Oshizu was rather ignorant of modern Japanese culture (such as why Buxom Is Better) and is fascinated by technology. In fact, the concept of dieting for the sake of getting thin is a Berserk Button for her, since she lived during times of poverty and famine.
Rito's "best" (for want of better description) friend since junior high, Kenichi is envious of Rito for all of his Accidental Pervert situations. He does, however, especially in the earlier chapters, support Rito/Haruna and sometimes goes out of his way to arrange time for the two to be together.
The runaway crown princess of Deviluke, having had enough of her father, Emperor Gid Lucion, forcing her into several Arranged Marriages, Lala first appeared on the scene by accidentally (or rather, conveniently) landing in Rito's bathtub... while he was in it. She winds up getting engaged to Rito, deeming him suitable enough to be her fiancÚ, though this was only to escape her father and her bodyguard Zastin. Eventually, Lala does genuinely come to love him and even encourages Haruna's love, despite the fact it interferes with her own.
Beware the Nice Ones: Sweet, good-natured and sunny she certainly is, so it's very easy to forget that she also belongs to a race of world-destroying warriors... who can fight the galaxy's best assassin to a standstill in unarmed combat, and taking on an Amazon Brigade empty-handed until they figure out her "weak point".
Corrupt the Cutie: Played with in some chapters. Lala's still her sweet bubbly self no matter what her female friends and peers try to get her to do regarding her relationship with Rito.
Surprisingly played straight in Darkness when Peke reminds Lala about her own personal happiness with Rito. She spends the entire afternoon clinging onto him like she usually does, but Rito naturally doesn't look too much into it. Cue Momo introducing her older sister to an 18+ dating sim and Lala later surprising Rito by teleporting into his bath tub much like she did at the start of the series. Only this time she has a reason for being in Rito's bathroom. That reason being she wants to experiment with kissing. But of course, in typical TLR fashion, things don't go as planned when Rito another one of his classic "accidents". In the end, Lala settles for giving Rito a kiss on the cheek.
Nice Girl: A sweet, bubbly girl who always tries to help whenever she can. She's even willing to share Rito with Haruna, so that everyone can be happy. Peke calls her out on this, reminding her that she should also care about her own happiness.
Pretty Freeloader: Possibly averted. Presumably Rito's parents are source of Rito and Mikan's money. They probably save enough on hired help by using Zastin et al that sending a bit more to their kids isn't a problem.
Shameless Fanservice Girl: Lala doesn't really seem to care all that much about anything like modesty or not being naked all the time, due to being used to having servants around to dress and undress her.
Vapor Wear: Supposedly, she dislikes wearing a bra.
Lala's bodyguard and the ace of the Devilukean military, Zastin was tasked to retrieve Lala until he was mistakenly swayed by Rito's words on Lala's Arranged Marriage, citing he truly understands the princess' feelings (though that wasn't what Rito meant). Choosing to stay on Earth to continue watching after Lala, Zastin in the meantime works as an assistant for Rito's father Saibai and is learning how to draw manga himself.
One of the deadliest assassins in the galaxy, Konjiki no Yami ("Yami", in shorthand) was originally hired by one of Lala's suitors to kill Rito, until a slip from his mouth reveals that Rito is not what he seems to be. Nullifying her client's contract, she turns against him and stays on Earth for the time being... all the while starting to have a crush on her erstwhile target herself, even as she continually threatens to kill him one day.
Accidental Pervert: She accidentally grabs Riko's naked boob, and gets screamed at: "That's shameless!". She is so conflicted over this reversal of their usual routine, that she can only react with incredulity.
Badass Adorable: She may be a cutie, but don't go getting any ideas. She despises perverts.
Badass Bookworm: Spends most of her time reading any book she can get her hands on.
Berserk Button: Anyone/anything she considers perverted. Poor Rito, being the Accidental Pervert he is, is her most frequent punching bag whenever he's in close proximity, even if she knows his latest mishap was an accident, only stopping short of killing him because she admits that she does know. Her Darkness persona expresses the opposite opinion and openly embraces her sexuality.
It's also not a very good idea to do anything to Tearju around her. Though that may be because she always catches Rito with her while she's naked...or in post-orgasmicafterglow.
If you value your life, don't ever threaten Mikan.
Expy: Of Eve from Black Cat, The T-1000 and possibly Fate Testarossa. As of Darkness, however, Yami is implied to be not just an expy, but an Alternate Universe version of Eve, which turns out to be also Yami's true name. And like her original, she's an enhanced clone of her creator, Tearju Lunatique.
Evil Costume Switch: Her "Darkness" form comes with a much skimpier outfit than her trademark one.
In Love with the Mark: How her relationship with Rito ultimately developed. The way the relationship started is the real reason why she loves taiyaki so much.
Lethal Chef -> Cordon Bleugh Chef: Her first attempts at cooking were rather horrid, though justifiable by her initial limitation of knowledge of Earth's cuisine to taiyaki, so she just put that in everything. Under Mikan's instruction she does quite well at cooking, but still has a fondness for taiyaki, which she expresses by creating taiyaki miso soup, something Rito had to force down.
Little Miss Badass: She looks to be the same age as Mikan but is one of the strongest fighters in the series.
Living Weapon: What she initially considers herself to be, having been indoctrinated as such.
One-Girl Army: What she was intended to be, and for the most part she lives up to her reputation.
Too Many Belts: Five totally pointless but sexy-as-hell belts wrapped around each leg (the lowest of which are hidden by her shoes). She cuts it down to one around her left leg when in her school uniform.
Weaponized Teleportation: In her "Darkness" form, she can form portals with her hair to send anyone near her to somewhere else, and instantly summon anyone she wants to her.
What Is This Thing You Call Love?: Much like Mea and perhaps Nemesis as well Yami doesn't quite get human emotions and love is one of them. Justified in that all she has ever known her whole life is killing.
Why Did It Have To Be Slimy Tentacles?:: Loathes ecchi things, especially tentacles. Though the latter of those seems to induce more of a panic in her than her standard response to anything else perverted happening to her. She mentions it being a result of being lost on a planet with tentacled monsters, but trails off quickly, obviously not wanting to talk about it.
Woobie, Destroyer of Worlds: A unique interpretation. In addition to her Dark and Troubled Past, her "creators" programmed the nanomachines that give Yami her powers with a "Darkness" mode that activates when she comes to accept the mere possibility of being able to live peacefully, turning her into a living weapon of mass destruction to make sure that the universe will never achieve true peace.
Yandere: In her "Darkness" form, she tells Rito that she loves him, and by killing him herself, he can live on in her heart forever.
Lala's younger sister and the younger twin to Nana, Momo is rather well-endowed for her age (much to Nana's angst) and the more mischievous of the twins. Both twins fled to Earth to escape their studies back on Deviluke. She has a unique ability to talk to plants. In Darkness she decides to come up with a plan to "make all the women in Rito's life happy" and calls it the Harem Plan.
Ascended Extra: Like Yami, Momo was a recurring secondary character, until Darkness promotes her as a protagonist.
Ax-Crazy: Has a violent side she keeps hidden, and can be a little sadistic when dealing with people who threaten her loved ones.
Beneath the Mask: Always puts up a smile in front of everyone, when behind the scenes she can be quite manipulative and violent. And also very horny. So far, only Nana, and to a lesser extent, Rito, knows of what goes on inside her head. Momo once even expressed regret over being forced to show her violent side to Rito, but not so much with her perverted side. It should also be noted that she mostly shows her violent side when someone threatens the people she cares about. Under her facade, she's actually a pretty nice girl.
The Fake Cutie: Puts on an innocent front to hide her true personality. Only a few characters, such as her twin sister Nana and the mentally mature Mikan, can see through her fašade. This is not exactly a bad thing, mind you.
Harem Seeker: A rare inverse version in Darkness, where Momo, herself a harem girl, is doing this not for herself, but for Rito. And oddly, she even wants to add girls who have shown no interest at all in Rito to the harem (even including Saki, the only girl with a clearly-stated romantic interest in a guy other than Rito).
Hidden Depths: At first glance, she's a sweet, kindhearted princess. Beneath that facade she's horny, manipulative, and has a serious violent streak. As Darkness progresses, however, we get to see more and more of her personality, and she's a surprisingly complex character. Her love for Rito is very genuine, and she's actually shown some hesitation when it looks like he's starting to respond to her advances. In addition to this, her violent side tends to come out only when someone threatens her friends and family. Even her "Harem Plan" is intended to give the various girls crushing onRito a happy ending with him. She may just be acting like The Cutie, but don't doubt that she's a good person.
Horny Devils: Not a devil per se, but a very naughty alien princess. Plus, she has a devil-like tail.
Jerk with a Heart of Gold: No matter how manipulative and naughty she can be, she genuinely cares for her family and friends.
Little Miss Badass: At the very least, she can dodge punches like Neo, then summon plants to take down her attackers.
Lovable Sex Maniac: Even moreso than Risa. Her current goal in life is to win Rito's love and affection not just because she loves him, but also so she can have sex with him.
Matchmaker Crush: While she actively pursues Rito to hook up with all his girls, his harem, nevertheless, includes herself, as she wants just as much affection from him, finding his "flushed face" cute.
Not So Different: Though she would never admit it, Momo isn't that much different from Nemesis in terms of making Rito feel uncomfortable sexually speaking. The only thing that separates them is Momo genuinely likes Rito whereas Nemesis more or less sees the young man as a "servant". Momo also cares about other people besides herself that she considers friends while Nemesis is only concerned with trying to make Rito hers (thus undoing all the work Momo has put into the Harem Plan) and activating Yami's true potential as a living weapon via the "Darkness" protocol.
Even more surprisingly, she's very similar to Rito. Later in the series, Rito's fantasies are just as explicit as hers, and when Momo has someone seriously come on to her, she freaks out and runs away, just like him.
Oh Crap: Has a really big one when she sees Mea transform into Nemesis.
Violently Protective Girlfriend: The most protective among Rito's love interests. When she thought Yami was trying to kill Rito and decided to interfere with their conversation, Yami commented that she could sense Momo's bloodlust. On another occasion, when her fan club tried to "save" her from Rito (by shooting him with Nerf Guns)... she wasnotamused◊.
Lala's younger sister and older twin to Momo. Having had enough of their studies back on Deviluke, she flees to Earth to pay Lala a visit (with Momo tagging along). Like Momo's ability to talk to plants, Nana can communicate with animals; unlike Momo, however, Nana finds it hard to believe why everyone around Rito likes him, having witnessed a few "incidents" that proves otherwise.
A-Cup Angst: Poor, poor Nana. It must be hard to grow up alongside Lala and Momo. She doesn't take too kindly to any derogatory comments or even things that she could interpret as a jab towards her lack of a bust.
Tomboy: Aside from using the informal-feminine "atashi" to refer to herself, Nana exclusively uses impolite-masculine Japanese in her everyday speech patterns, up to an indcluding the impolite suffix "-yagaru" (which can is the rough equivalent of "goddammit" or "the goddamn") in her sentences when she is bored or annyoed.
Father of Lala, Nana, and Momo, ruler of Deviluke and by extension the entire universe as we know it. He tasks Rito with fending off potential suitors who wish to have Lala's hand in marriage. Should he fail, the mysterious ruler of the cosmos threatens to kill not only Rito, but also blow up the entirety of Earth. Gid is rather antsy about when Rito will succeed him as king.
Chuck Cunningham Syndrome: Aside from him asking Zastin around chapter 100 or so how much longer Rito is gonna take before he gets serious with Lala and marries her so he can succeed the throne, and Zastin contacting him about Nana and Momo, he hasn't been seen ever since.
Dirty Old Man: The only reason (in the manga) why he wants his eldest daughter to hurry up and tie the knot with Rito is so he can look up girls skirts all day long.
Evil Is Petty: While not evil per se, should Rito fail in keeping Lala off potential suitors hands who also want to marry her, he will first kill Rito and then blow up the Earth.
The Reveal: Around chapter 46 or so, Gid personally visits Earth in an attempt to hurry along Rito's "courting" of Lala. Earlier chapters built him up to be a legitimate foreboding threat since Gid only bothered communicating via his voice leaving his identity to be a mystery. While Gid is not someone you want to fuck with, you may be easily forgiven for assuming that a seemingly perverted little kid couldn't possibly be the ruler of the universe.
A childhood friend of Lala, Ren hails from the planet Memorze (a planet shown by one of Lala's flashbacks as an Arabian-styled world). When they were children, Lala absentmindedly promised him to marry him should he become manly. Taking it for face value, upon arrival on Earth, Ren arrives to prove that he's manlier than Rito. Unfortunately, his pursuit leads to an unexpected circumstance with "Run", his alter-ego — and a girl both in body and personality — triggered by a sneeze. In direct contrast to Ren, Run is infatuated with Rito, leading her to become an idol in hopes of gaining Rito's attention.
Accidental Kiss: Ren with Rito. The surprising thing here is that this incident is what caused Run to fall for Rito.
Literal Split Personality: As of Darkness, Ren and Run have literally split into two separate individuals as a result of achieving a metamorphosis simply described as "reaching adulthood". Naturally, both have something to be happy about.
Rated M for Manly: Ren strives to be manly after Lala absentmindedly agreed to marry him if he did back when they were children.
School doctor of Sainan High, Ryouko is actually a former operative from an alien black market who wanted to overthrow Emperor Gid, then fled to Earth to hide from her former clients. Dr. Ryouko provides medical care to other extraterrestrials on Earth, but isn't above providing mysterious concoctions to her students.
Cool Big Sis: One of the few adult females in the series, who often gives advice and information to the younger characters.
Harem Nanny: Is pretty much the only somewhat sane female character next to Mikan.
Although with Chapter 27, she may be falling for Rito herself.
Show Within a Show: The star of "Magical Kyouko", an obvious parody of the Magical Girl genre — where else can you find a transformation that involves the girl going to the toilets to change, or troubleshooting by burning?
Lala's gift to Rito for his sixteenth birthday, Celine was a giant, sentient sunflower kept in his backyard. Like the rest of his plants, Rito makes sure Celine is cared for, even referring to it as his family. After Celine contracts a disease, causing it to dry up and germinate, out pops an infant Celine from the seed. Looking like a human child (except with a noticeable flower on her head), Celine lives with in the Yuuki household and occasionally calls Rito "Mama".
Love Potion: When she is drunk (with cola) the flower on her head can spray a pollen that temporarily causes anyone who inhales it to fall in love with Rito, man, woman or animal. It was theorized to be a side-effect from Celine's affection for her "Mama".
In one of the extra chapters from Darkness, we get to see how Celine's pollen works from a first-person perspective: It strongly induces sexual arousal in response to highly specific set of stimuli, i.e. anything related with Rito. Things like his voice, visage, presence and particularly his touch become huge turn-ons to the person infected with the pollen. Interestingly, it turns out that if said person already has an interest in Rito (eg. Mikan, Yami), they behave distinctly from the rest and are better able to control themselves, probably because they have an easier time differentiating their own feelings from the induced ones.
Overnight Age-Up: In one chapter she grew to resemble a preteen girl and then reverted back to being an infant.
Plant Aliens: Even as a plant, Celine behaves like a human — sweating when hot, wearing an oversized scarf when cold, and eating a giant bowl of ramen when hungry. Of course, she subverts it later and becomes a Human Alien.
Good Bad Girl: While the rest of the cast balk at the topic of sex, Mea shows great curiosity for it, and will openly talk about her fantasy of getting Rito to lick her, to the point of outright asking him to do so. Otherwise, she's usually a very friendly and upbeat person.
Grand Theft Me: She can, and has taken control of other people's bodies. Most notably she has done so to Rito repeatedly onscreen. This ability was also useful in rescuing Rin from a literally bloodthirsty sentient/empathic sword.
The foremost genius in the field of biotechnology, Tearju was part of a scientific team that created Yami and also provided her biological makeup, making her technically the latter's mother. She left the group, however, due to disagreements over treating Yami as a Living Weapon against Deviluke, and vanishes without a trace. In reality, she was being hunted down by her former clients, until she was found by her former classmate, Dr. Mikado, who convinces her to come to Earth in hopes to help her reconcile with her "daughter". She's currently a substitute teacher at Sainan High.
Expy: Of the same-named character in Black Cat. Darkness leans her towards being an Alternate Universe version, with the link between the two Tearjus being the character "Eve" (which happens to be Yami's true name).
Grand Theft Me: Chapter 39 shows that she can usurp Mea's body at any time, with little to no warning. There is also the fact that she can use Mea's ability (hair) to take control of other people's bodies.
Power Perversion Potential: Shares this trait with Yami and Mea, but Nemisis literally hits Rito in the face with this by aging herself up and subjecting him to Marshmallow Hell. Momo also notes how "convenient" it is.
Split Personality Takeover: It turns out that Mea was nothing but a split personality that Nemesis fabricated to get close to Rito and Yami, and Nemesis pulls this on her once Yami's Darkness protocol activates. It's later revealed that Nemesis lied to push Yami's Darkness protocol over the edge and that Mea is an actual person. It's just that they fused when the first met as Nemesis was physically unstable and Mea was mentally unstable.
The Vamp: Probably the most sexual character shown so far. She's far more direct than even Momo and is vastly more depraved.