The NK-13S Gundam Schwarzritter is a custom Gunpla introduced in Gundam Build Fighters Amazing Ready.

A modification of the NK-13 Cathedral Gundam, it is built and piloted by Masked Second G. The concept behind Gundam Schwarzritter is that if it is fast, there is no need to attack from a distance. As a result, this melee combat specialized Gunpla has extremely high mobility to avoid the enemy's attacks while closing in quickly, and will slice the enemy apart in melee range using large swords that also serve as its wings. This simple combat style also requires the fighter operating the Gunpla to have a high level of skill and the ability to make split-second decisions. Completed to an astonishing level of perfection, the Gundam Schwarzritter's name means "Black Knight" in German, and true to its name, it has a jet black body. It is later modified into the NK-13J Denial Gundam, which inherits its basic performance.