Talk:Amakusa Shirou/@comment-4802891-20171019075816/@comment-4802891-20171019142557

Muramasa can cut someone's karma, the course of actions that lead him to be what he or she is through hardship, mistakes and suffering. I guess he was able to rip through it because Reality Marbles are projection of one's mind, shaped by his one's life.

Why the hell would Muramasa of all people be able to do that is beyond my knowledge, but that's a cool concept!

Now, he isn't almighty and needs proportionally powerful weapons to cut down the karma of powerful enemies : for instance, here, he had to trace the Tsumugari-no-tachi (Kusanagi), a [presumed] Divine Construct, to destroy the RM, resulting in the depletion of his spiritual energy.

The fun part is, the destruction of the castle is apparently a secondary effect of his legend : Tokugawa Ieyasu was afraid of Muramasa's swords and ordered for all of them to be prohibited. As a Servant, this gives bonus damage to weapons made by Muramasa, against anything Tokugawa-related. Togejou/Onri Edojou, the big castle here, was built by the Tokugawa shogunate. lol