Saiki Kumagoro

 Kumagoro Saiki (斉木 熊五郎, さいき くまごろう lit. Saiki Kumagoro) is the husband of Saiki Kumi, the father of Kurumi, the father-in-law of Saiki Kuniharu and grandfather of Saiki Kusuo and Saiki Kusuke.

Personality
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. He surprisingly gets along with Riki.

He is also shown to be a tsundere is some episodes, like in S1 E19, Kusuo’s used telepathy on him and he appeared to be thinking about how he could spend some time with Kusuo. But it was just a dream.

Trivia

 * His name,, is a pun on the word Psychic (サイキック Saikikku), just like the rest of the Saiki family.


 * Kumi and Kumagoro's Japanese voice actors, Rie Tanaka and Koichi Yamadera respectively, were actually married at the time of their debut episode's production, but the two divorced in 2018.
 * He shares the same hairstyle, eye color, and blood type as Kuboyasu Aren.