Souda is described as having strong emotions despite trying to appear calm. His appearance does not match his timid personality, which makes people notice him. While he may try to hide it, Souda seems to be a poor liar, leading him to contradict himself at times. He has a tendency to speak impulsively and blurts out what he is thinking without filtering his words. This can lead to awkward situations for him, such as when he comments on Sonia's wetsuit or expresses jealousy towards Tanaka. Souda is skilled in repairing broken items using his knowledge of mechanisms. He has a fear of dying on the island and this causes stress and panic for him. He often carries around a spanner/wrench with him. Souda can be jumpy and tends to exaggerate his reactions, making him appear nervous or anxious at times. Additionally, he seems to have developed feelings for Sonia that may border on perversion, leading to jealousy towards Tanaka.
Souda's life before despair seemed to been fairly tougher than a normal child's. It is noted that he and his father ran his family's bike shop, but nothing was ever sold. The bike shop wasn't always inactive, however-- many customers would ask for them to fix their bike tires or inflate them. Despite this, the family was still often low on money. In result, though, Souda got plenty of practice with making and building things. As a child, Souda was very skittish, and easily picked on.
In addition to Souda's rough childhood, with money and bullying problems, his Dad seems to have constantly beat him. In one of his free time events, he states that he had never been on a field trip, and spoke quite casually about his father beating him when he didn't attend school on those days. This confuses Hinata, but Souda doesn't seem to register the severity of it. Such behavior suggests that he was a subject of excessive abuse.
Soudas life before despair seemed to been fairly tougher than a normal childs. It is noted that he and his father ran his familys bike shop, but nothi
He let other children step all over him, but before he entered Hope's Peak, he changed his appearance entirely. From changing his hair color, to losing his glasses, and assumedly sharpening his teeth, so that he could fit in better with people around him. It seems as if it'd do the opposite, but that may just be how his mind works. At this point, he began to put up the "Tough punk" facade to avoid more bullying, which, to this day, continues to break almost constantly.
Souda is one of the few people who survived at the end.