Zouken Matou

A shrewd, powerful, but ancient sorcerer, Zoken is patriarch of the Mato family and is known to be the grandfather of Shinji and Sakura. He has amassed a large and extensive library of sorcerous knowledge, yet his lessons are strict and harsh. Zoken considers Shinji to be a disgrace of a sorcerer, and believes Sakura may have more potential than her brother.

(Source: Wikipedia)