Masumi Seki is one of Punpun's childhood friends and Shimizu's best friend. He has a gruff personality and usually has a cold and indifferent expression, even when he is upset. There is a permanent scar above the bridge of his nose that is covered by a bandage throughout most of elementary school. His family owns Seki Lunches, which used to do business with the now-abandoned miso factory.

Keisuke Isobe is a young introverted teenager classified as a nerdy type.