Born April 1, Mendō is heir to the powerful Mendō Zaibatsu. His family has their own private army, a fortune of at least 50 billion yen, and owns 51% of Japan. In Vol. 3 of the manga, he transfers to Tomobiki High School. Handsome, athletic, and talented, all of the girls soon fall for Mendō. Mendō, however, is just as lecherous as Ataru and professes his "love" for all of them, sweeping them off their feet. In stark contrast to this, he treats all of the men of the class like dirt. He frequently parachutes to school from his private jet. Though he walks with a sense of pride and looks down on his fellow male students and their shenanigans, Mendō is actually very similar to them: he is obsessed with women (particularly Lum), he has no respect for Onsen-Mark (though he often pretends he does), he views Ten as a nuisance, and of course, he is jealous of Ataru.
In love with Lum, he very gentlemanly refers to her as "Lum-san" (ラムさん, Ramu-san?). But Lum is completely in love with Ataru and does not care about Mendō, so he views and treats Ataru as his greatest enemy, but in reality they are pretty much the same (Mendō is only a gentleman about it). However neither of them care to admit this. Despite his feelings for Lum, Mendō is not above flirting with other women and never dissuades their hopes of one day being with him. He even "reluctantly accepts" the idea of an engagement to Asuka Mizunokōji after he learns how cute she is.
Mendō is very easily insulted, usually by Ataru whom makes a fool of him on several occasions. On said occasions, Mendō draws his katana (in the anime it is called Murasame) and attempts to slice him in two, but he never succeeds as Ataru is capable of catching the blade in his hands. As the series progresses it becomes more and more obvious that, in addition to his libido, Mendō is far from perfect. Some, like Sakura and (after awhile) Shinobu Miyake, would even go as far as to call him "an idiot".
He is often accompanied by his own private security team, the Black Glasses Corps, who are to carry out his every order, which usually involves taking out Ataru. However, they prove over and over that they are just as inept and idiotic.
Mendō family crest is the octopus, and Mendō himself keeps several as pets. Furthermore, he is offended if people eat takoyaki in his presence.
Mendō suffers from nyctophobia and claustrophobia, and will often scream "It's dark, it's cramped, I'm scared!" (暗いよ狭いよ怖いよーっ, Kurai yo semai yo kowai yo~?) in a deranged state when enclosed in dark, tiny spaces. However, whenever woman are nearby he manages to remain calm. At one point, he put himself through harsh training in order to overcome these phobias, however this only resulted in him temporarily becoming strong enough to split a temple bell (his usually source of entrapment, thanks usually to Ataru) in half from the inside. Apart from this, his phobias seem incurable.
His name was originally meant to imply "Trouble Shooter" ("Mendō" can mean "trouble" when written with the kanji 面倒, and "shooter" is represented in Shuutarou). However, because of his situation and involvement with Ataru, his name has come to imply "Trouble Maker".
|Name||What They Call Mendou||What Mendou Calls Them|
|Oyuki||Okata (Sir/This Person) (once)||Unknown|
|Ryōko Mendō||Onii-sama (older brother)||Ryōko|
|Father||Shūtarō||Chichi-ue (father, very formal)|
|Mother||Shūtarō||Haha-ue (mother, very formal)|
|Black Glasses Corps||Waka (young master)||Unknown|
- "Waa!...It's dark! It's cramped! I'm scared!"
- "I refuse to die a poor beggar's death like this!"
- DAMN THE SUNSET!!
- Would you just cut the crap and say that you love her?!