Male protagonist of To Love-Ru and resident Chick Magnet, Rito's in love with Haruna when the series begins but after failing to confess to her he tries to have a nice soak in the bath until Lala teleports onto him... in the nude... yeah. Turns out she's an alien princess from a far-off planet and she's just looking for an excuse not to go home, setting off Rito's daily routine of trouble.
Accidental Pervert - Quite possibly a contender for Trope Codifier. Seriously, take a shot every time he manages to get into an "accidental situation" with any of the female characters in the series, and kiss your liver goodbye.
Accidental Kiss - With Ren. Naturally, Rito is pissed, and he takes it much worse in the manga than the anime. And by "much worse", we mean he kicks Ren's ass for it, starting with a flying kick and progressing to a Big Ball of Violence.
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 better as time goes on, but is still liable to freak out if it goes too far.
Beware the Nice Ones - While the manga less emphasized on this, Rito WILL hurt you when the time is right.
The best comparison is when Ghi Bree kidnaps and starts molesting Haruna. The manga version shows Rito trying a hit and run strategy, while in the anime... HOLY SHIT!
Chaste Hero - He's generally more concerned about his life being shaken up by the various adventures the girls bring than noticing any of their crushes on him.
Gender Bender - Happens five times, all thanks to Lala.
Harem Hero - Type I; of note is Rito will throw himself into the fray if he feels the need to, and will attempt try to defend the girls around him. Fortunately, To Love-Ru isn't a full-on Shounen manga.
Hates Being Touched - He doesn't like it when any of the girls cling onto him. This is more due to embarrassment than anything else.
He seems to be growing out of it though, and even stood up for Run when Yui chastized her for clinging to him.
Made of Iron - Good thing he is one, because he's a...
Nice Guy - A veritable saint for not snapping and/or forcing himself onto one of the (many) hot girls in the cast after all this sexy extraterrestrial insanity.
Sweet Tooth - Maybe: on at least two occasions we've seen him talking about sweets in his sleep, usually when he's feeling up the girl who has snuck into his bed wth him.
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 and was only using his shapeshifting powers to look like a roid-raging demon, but nobody told Rito about that.
This Loser Is You - Originally, though he does develop as a character over time.
Unwanted Harem - If he successfully obtains everyone in it as Momo plans to, he's going to have a lot of descendants.
Sairenji Haruna
Sairenji Haruna
One of two female protagonists in the original manga, Haruna's the Girl Next Door who manages to be both sweet and kind without annoying the fandom. She was Rito's initial love interest until Lala came along; Haruna, of course, likes Rito too. Having become best friends with Lala, she won't do anything to break up Lala and Rito's engagement and only tells Lala that she loves Rito so she wouldn't feel guilty about not doing so in the future.
A-Cup Angst - As a phase: while it didn't bother her (not like she was flat to begin with, anyway), but when the idea that Rito likes girls with big breasts gets planted into her head, she starts getting more depressed and self-conscious. It's only when she remembers a speech about inner-beauty by Rito while she was trying to reassure Nana (who suffers from this trope twice as much as her) that she snaps out of it and regains confidence in herself.
Covert Pervert - A recent chapter has her fantasizing about Rito bathing her. And by bathing we mean heavy petting with bathing undertones.
Demoted to Extra - Haruna began declining in appearances for quite awhile as Yui was slowly overtaking her spotlight. Understandable when you consider the fact the woman she was based on was the source of the Creator Breakdown that eventually resulted in the end of the original manga.
Head of the public morals committee at Sainan High, Yui's seemingly obsessed with everything being proper and decent. Much to her displeasure, most of Rito's troubles has dragged her along wtih 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.
Ascended Extra - Following a certain point in the manga, Yui was given more and more screentime as Haruna appeared less for subsequent chapters.
Butt Monkey - Initially when she's introduced: the harder she tries to keep law-and-order, the more screwy fate treats her.
He Is Not My Boyfriend - Almost completely in denial about her feelings for Rito — especially evident when she makes Valentine's Day chocolate for him and insists, even to herself, that it's just "obligatory chocolate". Right, Yui, you just keep saying that to yourself...
She's even in denial to herself. Even after fantasizing about getting married to Rito and pregnant, she's still trying her hardest to not admit her feelings to herself.
Ms. Fanservice - Semi-subverted, since it's usually against her will.
The school's queen bee who considers Lala her rival. Of course, her numerous attempts at showing Lala up just make her embarrass herself in the end. She has a crush on Zastin, and is dismayed to learn that he's Lala's servant.
Alpha Bitch - Played for laughs on some occasions, portrayed with sympathy on others.
Rito's younger, more level-headed sister, Mikan's way too mature for a normal 11 year-old girl, who learned to take care of herself quicker than normal 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.
Brother-Sister Incest - Subverted: it's really a crush, and quite one-sided on her part. However, the series skirts this trope quite a bit (such as Mikan telling her brother they were Not Blood Siblings just to see his reaction).
Wise Beyond Their Years - It's a worrying state of affairs when one of the most mature and emotionally stable people in the cast is 11 years old (10 in the anime).
It can also be inferred that by the manga's end she's 12, seeing as she's in her last year of grade school and the manga ended in the break between that and her entering middle school. Still, it doesn't change the fact that she's way too mature for her age.
Sawada Mio and Momioka Risa (Voiced by Chiemi Chiba and Ryoka Yuzuki, respectively)
Haruna and Lala's classmates and good friends, Mio and Risa are Those Two Girls of the cast. Both are more than willing to help their female classmates with their personal problems ranging from beauty to smarts, but aren't above groping them, though.
Bi the Way - Although Risa's aroused by the female form, that doesn't stop her from pushing Rito onto her bed and attempting to seduce him... but she was nice enough to relent when he faints from embarrasment/arousal.
Skinship Grope - Both are just too happy to "feel up" other girls.
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 "It's not the outside that's important. Rather, it's the inside!". Risa responds with this.
A 400 year-old ghost girl found wandering around in the 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, Dr. Ryouko Mikado creates an artificial body (with the same face and hairstyle as her ghost form) for her to inhabit. Oshizu begins working as an assistant nurse to pay off the expenses for the body.
Cute Ghost Girl - At first; granted, she was human, but technically no longer one. Subverted later on into a...
Fish Out of Temporal Water - Having remained within the old school building for four centuries, Oshizu's 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.
Giving Up The Ghost - She tends to leave her artificial body when scared or hit.
Psychic Powers - After being a ghost for so long, Oshizu developed decent telekinetic abilities. Unfortunately, her powers can go out of control when she's frightened.
Shipper on Deck - Supports Haruna being paired up with Rito.
Super Power Meltdown - When she's scared, her poltergeist-like powers will go berserk via...
Rito's "best" (if you could really call him that) friend since junior high, Kenichi's 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.
Bromantic Foil - In contrast to the more innocent Rito, although the latter still gets all the "incidents".
The second female protagonist in the original manga, Lala is the crown princess of planet Deviluke. She ran away from home after her father Emperor Gid Lucion Deviluke kept forcing her suitors for an Arranged Marriage. Arriving on Earth, she accidentally (or rather, conveniently) lands in Rito's bathtub... while he was in it. She winds up getting engaged to Rito, deeming him suitable enough to be her fiance, though this was only to escape out of the situation with her father and bodyguards. 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 - With her sweet, good-natured and sunny disposition, it's very easy to forget Lala's the princess of a world-destroying warrior-race... 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".
Ditzy Genius/Bungling Inventor - Has a wide range of quirky gadgets that she invented herself and gets straight A's in school as soon as she masters the Japanese language, yet has an emotional maturity level surpassed by Mikan.
To be fair, Mikan surpasses just about everyone in the series in that category.
Razor Wind - Sort of: a properly-motivated Lala can throw punches of compressed air strong enough to smash concrete. Since she rarely has interest in fighting, this is just as seldom-seen as the tail lasers.
Lala's bodyguard and the strongest in the Devilukean military, Zastin was tasked to retrieve the princess, until he's mistakenly swayed by Rito's words on Lala's Arranged Marriage, citing he truly understands the princess' feelings (though that wasn't what Rito had meant). Relegating to stay on Earth to continue his bodyguard duties for Lala, Zastin in the meantime works as an assistant for Rito's father Saibai and is learning how to draw manga himself.
Iron Butt Monkey - Of course, he is the best soldier of Deviluke, which explains his toughness.
Chew Toy - Literally: the first time Rito meets him, a stray dog starts gnawing the bone-like "armor" on Zastin's leg. The dog shows up, again chewing Zastin's armor, at least once more in the series.
Expy - To Creed Diskenth of Black Cat, at least in appearance and powers. Personality-wise, Zastin's no Yandere like Creed is.
No Sense of Direction - Justified since Earth is an unfamiliar environment to him in the beginning. Unfortunately, he gets hammered with this in subsequent reappearances that it mostly derails him.
Konjiki no Yami (Golden Darkness)/Eve (Voiced by Misato Fukuen)
One of the deadliest assassins in the galaxy, Golden Darkness was originally hired by one of Lala's suitors to kill Rito, until a slip from her client's mouth reveals her target is not what he seems to be. Voiding her client's contract, she turns against him and stays on Earth for the time being.
Berserk Button - Perverts and/or anything she considers Ecchi. Poor Rito, being the Accidental Pervert he is, usually gets beaten to a pulp when he's in close proximity. Hell, she'll even beat him up if she knows it was an accident. She sometimes claims the only reason she stops short of killing him is because she knows it was an accident.
Darkness indicates she's not simply Eve's Expy, but is her Alternate Universe counterpart. In fact, her real name is Eve, and like her Black Cat original, she's an enhanced clone of her creator Tearju Lunatique.
Lethal Chef -> Cordon Bleugh Chef - Her first attempts at cooking were rather horrid but justified since her understanding of Earth food was limited 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.
Older than They Look - "By the Chronos Galaxy calendar, I'm twenty-four thous..."
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 belt around her left leg when she's in her school uniform.
Younger sister to Lala, Momo is Nana's younger twin. Well-endowed for her figure (to Nana's angst) and the more mischievous of the twins, Momo fled with Nana to Earth to run away from their studies back on Deviluke. She has a unique ability to talk to plants.
Ascended Extra - Like Yami, Momo was a recurring secondary character, until the Darkness sequel ascends her to become the second female protagonist.
Momo only displays her real personality in front of Nana, and to a lesser extent, Rito. She has expressed regret over being forced to show her more violent behaviour in front of him, though she states she's perfectly fine showing her perverted side, regardless.
Harem Seeker - Specifically in Darkness; however, in a rare inversion for this trope and Tenchi Solution, Momo, a haremette, is doing this not for herself, but for Rito.
Matchmaker Crush - While she's actively attempting to have Rito hook up with all the girls around him, his harem, nevertheless, includes herself, as she wants just as much affection from him, finding his "flushed face" cute.
Horny Devils - Not a devil, per se, but a very naughty alien princess. Plus, she has a devil-like tail.
Ms. Fanservice - Momo takes it a step further than the usual level by getting in the bathtub with Rito, waking him up by straddling him half-dressed and so forth.
The thing that makes Momo stand out the most is unlike the other girls, where fanservice is played mostly for comedy, Momo knows exactly what she's doing. Her fanservice is derived of a more sexual overtone.
Single-Target Sexuality - Ignores all the guys who hit on her at school and only looks at Rito. Even when he changes gender, Momo doesn't seem to mind.
Younger sister to Lala, Nana is Momo's older twin. 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 her twin, Nana finds it hard to believe why everyone around Rito likes him, having witnessed a few "incidents" that proves otherwise.
Secret Keeper - Is aware of Haruna's feelings for Rito, to which the former states she hasn't told this to anyone. Nana promises to keep it secret until Haruna tells Lala about it.
Shipper on Deck - Despite not liking Rito nor understanding why Lala likes him, she's fond of reminding both Rito and the other girls he is Lala's fiance, after all.
Vague Age - While she and Momo don't look much older than Mikan (who's currently 12 as of Darkness), the twins enter the same high school as Rito as first years (roughly 15). This vagueness is lampshaded when Yui asks the girls if that is their age. Nana responds by telling her not to worry about it, and the Principal helped them out, although this doesn't prove anything as one of the Principal's favorite sayings is "It's okay because you're cute".
What Does She See in Him? - Doesn't understand why everyone (including herself) is falling for Rito's kind personality.
Ren/Run Elsie Jewelria
Run, Ren
Ren/Run Elsie Jewelria (Voiced by Fuyuka Oura)
A childhood friend of Lala's, Ren hails from the planet Memorze (one of Lala's flashbacks indicates the Memorze clothing style has an Arabian Nights look to it). When they were children, Lala said if Ren became more manly, she'd marry him. Taking it for face value, Ren upon arriving to Earth becomes determined to prove he's more manly than Rito. Unfortunately, his pursuit of Lala leads to an unexpected circumstance with "Run", Ren's Gender Bender alter-ego. Anytime he sneezes, Ren turns into Run, female in both body and personality — and vice-versa. In direct contrast to Ren, Run's infatuated with Rito, leading her to become an idol in hopes of gaining Rito's attention.
Accidental Kiss - Ren with Rito; in fact, it's because of this that Run falls for him.
Gender Bender - Memorzeans can change genders via a particular stimulus. In Ren/Run's case, it's a sneeze, though it's supposed only that easy when they're on Earth.
Pepper Sneeze - In case he/she needs to change gender on the fly.
Literal Split Personality - As of Darkness, Ren and Run no longer share one body: they have literally split into two as a result of them achieving a metamorphosis simply described as "reaching adulthood". Naturally, both have something to be happy about.
Rated M for Manly - Ren strives to be as manly as possible, since Lala absentmindedly agreed in their childhood to marry him if he did.
The school doctor at Sainan High, Dr. Ryouko is a ex-operative for a black market-based alien organization who wanted to overthrow Emperor Gid's rule of the galaxy, but flees to Earth in hopes of hiding from her former clients. Although primarily a school doctor, Ryouko does provide medical care to other extraterrestrials on Earth, but isn't above providing mysterious concoctions to her students.
A half human, half alien idol, Kyouko's the star of her own television show "Magical Kyouko", where her motto is "Whatever the problem is, I'll solve it by burning it!" She works alongside Run and becomes fast friends with her.
Big Bad - Played with in the Trouble Game arc, though this was only a simulation.
Expy - Based on the same-named girl from Black Cat, even sharing the same seiyuu, but her personality is different.
Its also a bit of a parody: where else can you find a Magical Girl transformation that involves the girl going to the toilets to change, or says "Whatever the problem is, I'll solve it by burning it!"
Lala's gift to Rito for his 16th birthday, Celine is a giant, sentient sunflower kept in the backyard of his house. Like the rest of his house 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 - The flower on her head can spray a pollen that temporarily causes anyone who inhales it to fall in love with Rito, be it man, woman or animal. Theorized in-universe to be a side-effect from Celine's affection for her "Mama".
Plant Aliens - Even as a plant, Celine behaves like a human: sweating when it's hot, wearing an oversized scarf when it's cold and eating a giant bowl of ramen when she's hungry. Of course, she subverts it later and becomes a...
An alien girl introduced in Darkness who claims to have been created by the same organization as Yami. She has been sent to Earth on a mission to take her "big sister" back.
Beware the Nice Ones - Seems to be quite nice, but is a very strong and ruthless fighter.
Bi the Way - Spends a good portion of one chapter groping and/or licking Riko, because she was cute.
Genki Girl - Is almost always smiling and energetic.
Good Bad Girl - While the rest of the cast balks at the topic of sex, Mea shows a great curiousity for it, and will openly talk about her fantasy of getting Rito to lick her all over, even to the point of outright asking him to do so. Despite this, she is usually a very friendly and upbeat person.
Secret Keeper - She knows about the "Harem Plan", but despite semi-conflicting orders, has chosen to support it. However, she won't help Momo where it comes to Yami.
The foremost galatic prodigy in the field of biotechnology, Professor Tearju was part of a scientific group that created Yami; Tearju provided her biological makeup, making her what amounts to Yami's mother. She left the group due to disagreements over treating Yami as a weapon of war in hopes to overthrow the Devilukean Empire, and vanishes with a trace. In reality, Tearju was being hunted down by her former clients and had to escape with her life. Dr. Mikado, a former classmate of Tearju, finds her late in Darkness and convinces her to come to Earth in hopes to reconcile with Yami. She's currently a substitue teacher at Sainan High.
Expy - Of the same-named character in Black Cat. To Love-Ru Darkness, however, leans this towards an Alternate Universe counterpart, with the link between them being the character "Eve" (Yami's true name being Eve).