Full name: Seiichi Matsuda. Though not related to Ikari, they were found abandoned in the same box as infants and grew up together. Like Ikari, he has dimples and prominent canines, though Seiichi has a more friendly, approachable face. He has a dog-like personality—loud and energetic. Standing at 191cm, he is just 1cm shorter than Ikari. He is with Ikari 24/7; they bathe, go to the latrine, eat, and sleep together. He is heavily codependent, never wanting to be apart and thinking things like "don't touch my Koyuki." While he is on decent terms with the rest of the 7th Division, there is a clear distance compared to his bond with Ikari. He is the type who can't lie; everything shows on his face or comes out of his mouth. He's comfortable with kissing or sexual acts as long as it's with Ikari. In fact, he wants to.