Kazuichi Soda is the Ultimate Mechanic. Despite his "punk-rock" exterior, he is known for being one of the most emotional and easily frightened members of Class 77-B. Kazuichi’s look is entirely manufactured to hide his past as a bullied, nerdy student who wore glasses and had black hair. He wears a bright neon yellow-green jumpsuit and a grey beanie to cover his messy, hot-pink dyed hair. He has pink eyes and has sharpened his teeth into "shark teeth" to appear tougher and keep people at a distance. Though he looks like a delinquent, he is a major coward who screams frequently and is prone to intense panic. Ironically, the world's best mechanic suffers from severe motion sickness and can't actually ride the vehicles he builds. He is infamously obsessed with Sonia Nevermind. His ex attempts to woo her often cross the line into creepy stalking, leading to a one-sided rivalry with Gundham Tanaka. Due to a childhood betrayal by a best friend, he struggles to trust others, which makes him appear cynical or paranoid at times. Kazuichi's pervertedness stems from typical teenage hormones to a genuine yet questionable fascination. He apparently likes the idea of undressing a girl and checking out her bone structure, thinking it's similar to dismantling machines. He seems to think it's normal, though Hajime is weirded out by this and calls it a fetish.[70] His dirty curiosity repeatedly outweighs his fear of being branded a pervert, leading him to infiltrate events that are off-limits to him, often dragging Hajime along as cover. His childish streak shows most in his nosy, almost playground-level curiosity about which girls his male classmates are 'targeting,'[4] even in the middle of serious situations like class trials. Even a simple hangout is enough for Kazuichi to jump to conclusions about the two engaging in something sexual.[72] He is transmasculine (assigned female at birth but transitioned to a guy).