Souma's the kitchen staff member you'd describe as laid-back, though his easygoing vibe comes with a catch—he's basically a professional at manipulating coworkers into doing his job while taking credit for their "generosity." It works on almost everyone except Inami, who doesn't bother waiting for him to pitch his scheme before throwing a punch. He's genuinely scared of her, and honestly, he owes Souta a debt of gratitude for existing, since Inami redirects all that violent energy toward Souta instead of him.
He keeps his personal life locked down and will dodge any question about himself pretty quickly. That said, the fact that he calls Satou "Satou-kun" hints he's probably over 20—the casual diminutive suggests some seniority on his part, though he's clearly not the type to volunteer that info.
Content compiled by AnimeList.moe from publicly available sources.