The male protagonist. He is the heir of the Shuei Yakuza Group. He made a promise to to a girl 10 years ago but doesn't remember who she is.
Accidental Pervert: Has a tendency to get into embarrassing situations with the female characters.
The Beard: For Chitoge in order to keep peace between their families. He also does it for Marika when her friend Mikage visits. Then Ruri when she visits her great-grandfather. Then Seishirou when she has to infiltrate a cruise ship for a mission. He does this a lot is what we're saying.
Becoming the Mask: He comes to develop genuine feelings for Chitoge over time, not that he has realized it yet.
Childhood Marriage Promise: He promised to marry his childhood friend if they ever meet again. It's eventually revealed that he, Chitoge and Kosaki played together as children and he visited Marika in the hospital, and promised all three.
Clueless Chick Magnet: He was actually very popular with the girls in middle school, but too dense to figure it out. In the present, other than Marika he doesn't really notice anyone else's feelings.
Crouching Moron, Hidden Badass: The pilot version of him KOs Claude with a Megaton Punch to the face. Current Raku doesn't fall behind either. For one, he calls out Tsugumi, a hitman, on her over-protectiveness of Chitoge saying she's nowhere as weak and needing protection as the Beehive group seems to think, gives a Dope Slap to Hana, The Dreaded imposing wife of a gangster boss that she has wrapped around her little finger and that no one in their right mind would piss off, followed by calling her an idiot over her treatment of Chitoge (and succeeds), and talks down the boss of a criminal organization that was Tsugumi's target without even flinching. Butt Monkey he may be, but Raku has massive balls.
Jerk with a Heart of Gold: He can be brash and rude, yet his luck with women probably stems from the fact that no matter how annoying he may find them he still wants them to be happy, and will go through a lot to make sure they are.
KidAnova: He made promises with not just one, but three girls when he was five.
Loose Lips: Initially, Raku just can't help denying his relationship with Chitoge, even though it is made very clear to him that his life will be in danger if that relationship is exposed as phony.
Love Makes You Dumb: His crush on Kosaki can severely affect his rationality, dangerously steer him towards Too Dumb to Live territory. One example is when being in a open-air bath full of women due to Claude's scheme, he manages to find a connecting drain which can get him out undetected. However, he hesitates when the girls gleefully tease Kosaki about who her first love is, making her run to where Raku is and block the exit before he can reach it. He only manages to escape thanks to Chitoge, who berates him for wasting his chance. Even worse, since he subconsciously believes that Kosaki is too good for him, he just assumes that the girl he pines for doesn't return his affections, despite many signs of the contrary.
Mistaken for Cheating: This is why Haru hates him so much at first, believing him to be lusting for her sister while being in a relationship with Chitoge, unaware that said relationship is fake. However, Kosaki isn't actually the only girl he has feelings for...
Supreme Chef: He is a great cook. He often makes food for his yakuza subordinates. He can even create new delicious recipes.
Too Dumb to Live: This guy just can't keep his mouth shut about his fake relationship in order to protect his own life, but has coped better over time. Still, his crush on Kosaki can still cloud his judgement, making his life unnecessarily in danger.
Tsundere: He can pass a lie detector test saying that he likes Chitoge and without his memory he's very sweet and kind to her. Much to her surprise, he also thinks she's quite pretty, but he would never admit it normally. When Chitoge's mom calls him out on how much he tries to take care of Chitoge he basically just refuses to think about it.
Unwanted Harem: He only admits to liking Kosaki, but is in denial about Chitoge. To make matters worse, he also has to deal with Tsugumi and Marika and he has displayed an attraction to both of them from time to time as well. Eventually, he also gets Kosaki's sister Haru and his childhood friend and new teacher Yui included in his harem.
Tsundere: She's abrasive, haughty and violent to Raku when she actually doesn't hate him as much as she claims. She continues to act the same even after actually falling in love with him, resulting in herself lampshading her inability to be honest about her feelings.
Cannot Spit It Out: She gets opportunity after opportunity to tell Raku how she feels about him, but never takes the chance. Even if she does try to confess, something will prevent her message from getting through to him.
No, Except Yes: Her response to Raku asking if she was giving him love chocolate. It was obligatory chocolate, just a "special" kind of obligatory chocolate. Raku is predictably confused, but understandably in this case.
Beauty Mark: Has one beneath the corner of her right eye.
Bifauxnen: Due to her Tomboyish Name and her tendency to wear clothing intended for men, practically everyone mistakes her for a pretty boy. Claude still hasn't figured out that she's a girl after knowing her for ten years. Tsugumi isn't really bothered by it so she usually doesn't correct people about her gender.
D-Cup Distress: She's very uncomfortable with her large breasts, as seen in episode 18, especially because Chitoge made her wear a skimpy swimsuit. Both Chitoge and Marika groping her shortly afterwards didn't help much.
Even the Girls Want Her: After Seishirou is discovered to be a girl by the students, one of the boys mentions that the girls should stop paying attention to her now. Unfortunately for them, the girls still fawn over her, and rush over shortly after he says that.
Gag Boobs: Her bust, being the biggest among the main female cast, is used as a source of humor from time to time.
Raku's self-proclaimed fiancée and the daughter of the police commissioner.
Accent Relapse: Her native backwater-sounding dialect is completely at odds with the cultured persona she cultivates, so she takes great care to speak like the others. It reverts when she's completely flustered, becomes angry, or being visited by a childhood friend from her home.
Animals Hate Her: And she's also scared of them due to a traumatic experience in her childhood involving hamsters.
Bad Liar: Normally when asked about her past she feigns ignorance and avoids the question, but if forced to lie, it's often extremely obvious.
Book Dumb: Definitely not stupid, but her ability to study is pretty poor due to her focus on becoming the perfect woman for Raku, and she will even sabotage her own chance to pass if it means getting more time to spend with him.
Childhood Friend Romance: She has been in love with Raku since she was little and unlike Chitoge and Kosaki, it doesn't take a while for her to recognize him.
Foil: Marika serves as a foil to Kosaki. Both are girly girls head over heels for Raku, but, unlike Kosaki, Marika has no problem being completely open about her feelings, aggressively pursuing him, whereas Kosaki usually needs Ruri's help to summon any courage.
Forgotten First Meeting: Another forgotten childhood friend of Raku. Marika doesn't take it well when she finds out Raku forgot about her after she devoted her whole life to him. She was also friends with Chitoge, Kosaki and Tsugumi.
Genre Savvy: She seems to know about Chitoge's antics, and believes Raku is being forced into that relationship.
Girly Girl: Became like this to be Raku's ideal woman.
Plucky Girl: Totally dedicated to cultivating her "refined" image and be a woman worthy of Raku. Hence, she undertakes every kind of training and work she feels necessary for achieving those goals. She also manages to resist a love potion's effect through sheer willpower.
Romantic Two-Girl Friendship: Mikage Shinohara is probably the only person, sans Raku and her father, whose opinion Marika actually cares about.
Secret Keeper: While it's clear she doubts the legitimacy of Raku's and Chitoge's relationship, she doesn't make any outright moves to reveal the truth to everyone else (though she will still shamelessly flirt with him). However it appears she is the one with the most to hide in regards to what happened 10 years prior, being the one who has the clearest recollection of the promise everybody is trying to figure out.
Short Hair With Tail: Most of her hair only reaches her chin, but two long "tails" are grown out on both sides.
Single-Target Sexuality: She has been in love with Raku all her life, never showing the slightest interest in anyone else. Of the girls that took the Love Potion that caused them to fall for Seishirou, she is the only one able to resist.
Sitcom Arch-Nemesis: She seems to actually enjoy being this to the other girls, especially Chitoge and Tsugumi.
Also with Yui who enjoys teasing and messing with Marika, but actually adores her. Marika, on the other hand, despises Yui.
Stalker with a Crush: She's rather obsessed with Raku and grabs him whenever she gets a chance, and she implies she put a tracker on him on some point.
Supreme Chef: Capable of making extravagant meals that both look and taste good. She says she has been honing her cooking skills for his sake. She even has a license for puffer fish preparation, something heavily regulated and quite difficult to obtain since the slightest misstep in preparing said fish can be literally lethal.
The Tease: Loves to do this towards Raku. She takes it up a notch anytime Chitoge is watching just to get a reaction out of her.
While she is certainly good at giving it, she is easily flustered when someone else manages to tease her, or Raku does his usual thing.
What the Hell, Hero?: Marika loses her usual demeanor as Raku delivers a stream of Armor Piercing Questions about not remembering who she was and only having vague memories of the meeting ten years ago. She lambastes him, stating everything she's done for him in the last ten years, such as thinking about him every day and growing her hair longer because he said he didn't like girls with short hair.
Voiced by: Koji Fujiyoshi (vomic), Yuuki Kaji (anime)
Cat Smile: Often has one, especially if something perverted is going on.
The Chew Toy: Shuu winds up on the wrong end of a lot of abuse, especially from Ruri.
Chivalrous Pervert: As shameless and obnoxious as he is about being a pervert, he does gently reject a girl for confessing to him since he doesn't return her feelings and it wouldn't be fair to her. He even thanks her for having the courage to confess.
Hot for Teacher: Has a crush on his homeroom teacher, Kyoko. After she rejects him, he says he needs some time to move on.
Jerk with a Heart of Gold: Despite his constant teasing, Shuu is quick to notice if any of his "friends" are hiding something or feeling down, and in his own way will try to help.
Megane: He actually seems to be proud of his glasses, acting as if they give him special privileges.
Obfuscating Stupidity: He's actually quite observant and perceptive, but prefers to act like a goof most of the time.
Shipper on Deck: He tends to support the Raku X Chitoge ship, though he doesn't seem to mind watching the other girls go after Raku as well.
Stepford Smiler: Part of his tendency to not let his actual feelings show that much, he went around smiling and acting cheerful when he learned Kyoko-sensei was getting married and retiring. Raku saw through it and mentioned that he'd had said tendency since he was a little boy.
Academic Athlete: She gets pretty good grades and is also the best swimmer of the school swim club. It's revealed in Chapter 102 that she has broken several swimming records during middle school and is known as "The Mermaid."
Sugar and Ice Personality: She mostly comes off as cold, blunt and harsh, but she has a very apparent soft spot for those she cares about.
Tsundere: She calls Shuu a "complete voyeur-camera perverted scum" and gets furious when someone jokes about the possibility of them having feelings fo each other. Still, she clearly has a thing for him, not that she's going to admit it.
When She Smiles: Played with. Shuu gives her a picture he secretly snapped of a rare candid moment of her smiling right after she regretted not smiling in the last photo of her with her grandfather just before he died. It's quietly hinted that Shuu liked seeing that side of her.
Raku's childhood friend who is a couple of years older than him, the don of a Chinese organization and the main cast's new homeroom teacher. She is also the holder of the fourth, and supposed last, key.
Selective Obliviousness: For such a professional like him, it never crosses his mind that Seishirou may actually be a girl, even after she decides to wear a ribbon.
Stalker with a Crush: If putting Chitoge's portrait right next to him when eating or having a nosebleed when looking at her in a bikini through his binoculars is any indication.
Well-Intentioned Extremist: Well...he wants Chitoge's well-being...but he is far too possessive and obsessed with her for his intentions to be even considered remotely good, and it's very clear he's nothing but a negative influence on Chitoge's life because of that.
White Hair, Black Heart: His schemes to bring Raku down come from sheer possessiveness and pettiness rather than desire to protect Chitoge.
Tsugumi's fellow hitman. She wants Tsugumi's approval and tries to help her make progress with Raku. Unfortunately, she's alarmingly incompetent at everything apart from being a hitman and is easily frightened.
I Want My Beloved to Be Happy: She eventually realizes she has a crush on Raku, but decides to support her sister instead and let them be happy together.
Jerkass: To Raku, whom she treats with nothing but irrational and petty contempt.
Loves My Alter Ego: She's in love with the "prince" who saved her from a gang, but she doesn't know and refuses to believe he is actually Raku. She eventually realizes those two people are one, and has trouble abandoning her love with Raku for the sake of her sister since then.
Matchmaker Crush: She decides to support her sister's relationship with Raku, but there's the issue of her own feelings for him.
My Sister Is Off-Limits!: Doesn't want Raku to be with her sister at first due to a misunderstanding. After realizing Raku is a really nice guy and that her sister likes him, she decides to support their relationship.
No Sense of Direction: Sometimes she can't even tell what floor she is on in a mall even though there is a sign.
Rescue Romance: She loves the "prince" (Raku) who saved her from a gang.
Shipper on Deck: After learning she misjudged Raku she tries to get him and her sister together; though that gets complicated because of the Sibling Triangle.