Pastor Nick is a member of a religion that worships the Walls as holy.

He claims that he lost his family as a result of addiction to Vine.

As a religious leader, Pastor Nick used his influence to oppose any modification of the walls, be it permanently sealing the gates or even mounting cannons on the top.


(Source: Shingeki no Kyojin Wiki)

Note: Minister Nick is the official English translation by Kodansha.