Mei's Grandfather is the father of Shou Aihara and serves as chairman of Aihara Academy. He's known for being ruthless and stern—the kind of guy who rules through intimidation and doesn't smile. He runs a tight ship at the academy, believing heavy discipline is essential to maintaining their prestigious reputation, much like Mitsuko, the previous school president who basically governed through fear.
That said, he's not entirely heartless. He gave Yuzu a second chance after she called him "grandfather" at the school gate and even overlooked her outburst during assembly. But when he caught her half-dressed on Mei's bed, that was the line—he expelled her without hesitation. He only let her return after she called an ambulance for him, which showed he does respect genuine character when he sees it.
So while his cold, calculating demeanor makes him seem impossibly strict, he's proven capable of forgiving people who demonstrate they deserve it. It's just that you have to earn it.
Content compiled by AnimeList.moe from publicly available sources.
