Oji-san おじさん

A middle-aged man with a perpetual grin, he is Alpha's closest neighbor and a regular customer at her café. He runs a gas station and sells vegetables on the side. He is a grandfather-figure to Alpha and the actual grandfather of Takahiro. Ojisan refers to himself as a bum and seems to regret not pursuing a relationship with Sensei when they were younger. His real name is never given.