Hiro is the Sheep of the zodiac, and he's basically the smart kid who uses it as a weapon. He's sharp and intelligent, but also verbally aggressive—prone to sarcasm and pessimism in equal measure. The guy's got a real sophist streak, loves to argue, and isn't afraid to be a smartass about it.
He's got it bad for Kisa, which explains why he starts out absolutely hostile to Tooru. As far as Hiro's concerned, she's constantly stealing Kisa's attention, and he resents her for it. That said, he doesn't stay a complete jerk. Over time, he softens up—part begrudging respect for Tooru's actual character, part Kisa literally telling him to chill out. By the end of it, his initial antagonism mellows into something more bearable, though he never quite loses that sharp edge.
Content compiled by AnimeList.moe from publicly available sources.
