Shuutaro Mendo is heir to the Mendou Zaibatsu with staggering wealth and its own private army. He commutes to school in a gigantic helicopter that is more like a flying mansion. Shuutaro carries a samurai sword which he often tries to use on Ataru (who has become expert at blocking it with his bare hands). Although very handsome he is just as stupid and lecherous as Ataru (just much more sophisticated in his approach). He takes his role as heir to the vast Mendou fortune extremely seriously. Mendou is vain, narcissistic, charming, overly dramatic, claustrophobic and afraid of the dark. He loves Lum, tolerating the presence of Ataru in order to be close to her. Shinobu is the closest thing he has to a girlfriend. (Source: Wikipedia)
In Japanese "Sakura" means "cherry blossom." She was once a very sickly girl who suffered from a variety of ailments. Many of them were the result of spirits that infested her body. On the advice of her uncle Cherry, she tried to exorcise Ataru, during which process, the demons who inhabited her transferred themselves to the unlucky young man. The second time she attempts to exorcise him, one of the demons possessing Ataru causes him to pounce onto her and suck her breast. Now in perfect health, Sakura is the Tomobiki High school nurse and a Shinto priestess or miko. Unlike her mother (who looks exactly like Cherry), Sakura is tall, slender and physically attractive, which makes her a common target of the lecherous boys of the school and even Mr. Onsen-Mark. The boys have been known to purposely injure themselves in order to see her. Like her uncle, she possesses an enormous appetite and has been known, despite never seeming to gain an ounce, to out-eat him. Sakura is extremely powerful and can summon foul and baleful creatures from Japanese folklore, by virtue of her mystical training. (Source: Wikipedia)
His nickname is derived from his hairstyle ("permanent"), he is tall and skinny (though his nameless Manga counterpart had quite a fatter form). Perm often displays the most character development, including being the only one of the Stormtroopers to have a visible girlfriend.
She is a high school student of Central High School. Her real name is unknown. She is overly conscious with the proximity of high school boys to her and often thinks too hard of what to do to escape the situation. In the train though, she decides to tease boys who happen to stand or seat near her by moving away. The main trio each had a chance encounter with her; all of them subsequently making her feel more conscious about herself. She is an acquaintance of Yassan.
Son of a Yakuza family. He's intelligent but not an adept fighter. He likes sweet things, wants to marry a Yamato Nadeshiko and says he's the kind of person who has to do it absolutely correctly when he puts his mind into something otherwise he can't be satisfied. Raku once got amnesia. He tried to save Chitoge from a wild ball that unintentionally aimed for her head. Unfortunately, it hit his head mercilessly. He was unconscious and then woke up a second later. He did not recognize anyone, even though all of his friend were beside him. He became a really sincere person. He charmed everyone who talked to him—even Chitoge, Tsugumi, Tachibana, and of course Onodera. During his amnesia period, he stayed at Chitoge's mansion. After some quarrel with Chitoge, it seemed like he hinted about the one who holds a key. It was also unclear though because he immediately regained his memory. The hint regarding the girl who holds the key to his locket is "the girl's eyes were either brown or black but not blue." In the end, Raku realises that he has feelings for Chitoge, rather than Onodera. While Onodera confesses to him, and turns out to be the girl of the promise, he rejects her confession. He tells Chitoge that he loves her, and she confirms that their feelings are both mutual.
Lum (also referred to in English dubs as Lamù) is a beautiful Oni alien who is capable of flying and generating electrical shocks. She is extremely popular and is famous for ending her sentences with ~datcha (loosely translated as "yes?" or "you know?"). Except when in her school girl's uniform, she usually wears a sexy outfit consisting of a tiger-striped bikini and knee-high go-go boots. While generally good-natured, sweet, and innocent, Lum also has a very hot temper. Her dream in life is to live in a "Sweet Home with Darling" in which she keeps house and raises babies while Ataru works. Unfortunately, Lum's idea of "cooking" is to take very spicy ingredients like jalapenos, cayenne peppers, and Tabasco sauce and irradiate them with an alien energy bazooka until they carbonize into inedible, crystallized nuggets. As an alien she has access to many bizarre gadgets whose use she really doesn't understand all that well, leading to comedic results. Differences between human and "Invader" physiology also drive many stories, like the time Lum's horns begin to grow larger after she is bitten by a cow, or the time she becomes drunk by eating pickled plums. (Source: Wikipedia)
His nickname is derived from his height ("chibi" means "small" or "short"), he is a timid crybaby, speaks with a cracked voice, and is often beaten up by the rest of the Gang of Four. He is often together with Kakugari. He also has buck teeth like that of a beaver's (though his nameless Manga counterpart did not have this).