Shigemori Sumimura

The grandfather of Yoshimori and the 21st head of the Sumimura family. He tends to be a very hot-headed fellow. In the Japanese version he is nicknamed "Shige-jii." We know that Shigemori is a very skilled Kekkaishi; in one episode the powerful Masamori and him talk, Shigemori: "You have become very powerful Masamori"; Masamori: "But I'm not even near your power."

(Source: Wikipedia)