Magus of Sealing Designation

Magus targeted by a sealing designation are those who have left the Mage’s Association’s umbrella to secretly research and pursue new knowledge. a sealing designation is only targeted at magus who the Mage’s Association deems to possess especially rare or unique powers. In order to preserve these rare and unique powers, the fate of one targeted by a sealing designation is to be imprisoned for life. Therefore, anyone targeted tend to leave the Mage’s Association and live in hiding. Kiritsugu’s father Norikata has been targeted by a sealing designation. Norikata is thus targeted by both the Holy Church and the Mage’s Association, to be eliminated for heresy, and to get a hold of his research, respectively.

Fate/Zero Animation Guide II: Glossary of the holy grail war II