Atsumu is a second-year setter at Inarizaki. He is more brash and reactive than his twin brother, Osamu. Outwardly, Atsumu appears to be a carefree, confident person who's usually seen with a lazy smile on his face, though he enjoys provoking people and giving offhand compliments. He can be quite condescending, childish, and a bit selfish at times. He is also a perfectionist who has ridiculously high standards for himself and others. He is a determined and competitive person who hates losing. 