The first thing you will need to do is own the The Dark Horizon DLC, as the sword was added in that expansion. Once you have it installed, make your way to Brabus in Ward 13 and buy every weapon ...

Guts has two notable weapons, those being his prosthetic left arm and his oversized Dragon Slayer sword. While Guts' left arm is cool with its built-in cannon and arrow launcher, Guts' sword is ...