Mendou is a very wealthy young man. His family owns their own army that is larger then Japans! He has a bunch of masked men at his disposal, who do his bidding and call him "Young Master" You think with all his wealth and good looks that he would be happy...but guess again. He wants the one thing that his money can't buy..Lum. This could possibly be the biggest reason he hates Ataru so. When you get right down to it, Shutaro and Ataru aren't very different from one another, Mendou is just very good at hiding that part of himself, while Ataru likes to flaunt it!

Mendu tries desperatly to be a proper young man, but having women practically throw themselves at him, you can bet that it's probably difficult for him at times to act so proper. He flaunts that he's rich, handsome and powerful, but he has his share of flaws, he can be egotistical and he has a big fear of the dark, that is until he hears a women, sees one or one sees him, then his fear dissapears. Ataru knows this and has used it to tease Mendou.

Mendou Shutaro follows the way of the samurai, he doesn't back down from a challenge and doesn't take well to failure. He also treats women as goddesses addressing them as Miss and often holding the door open for them, protecting them from Ataru or paying for there meal ect, and with this gentle treatment he's pretty much captured their hearts, this makes Ataru jealous and often times he is trying to show them his flaws.

Shortly after Mendou's arrival to the Tomobiki high School, we notice Shinobu kinda let's go of Ataru and falls in love with Mendou. Her love is misplaced though, because Mendou never notices really or just doesn't care how strongly Shinobu's feelings are for him.