Kumagoro Saiki is the husband of Kumi Saiki, the father of Kurumi, the father-in-law of Kuniharu Saiki and grandfather of Kusuo Saiki and Kusuke Saiki. Kumagoro is a grumpy old man who hates Kusuo's father Kuniharu and loves his daughter Kurumi. He is actually a tsundere who truly wants to dote on his grandchildren.