As I understand it, Nightblood is most comparable to a Shardblade. However, unlike a Shardblade, Nightblood requires constant input of Investiture in order to realize his full destructive potential. Why is this?
Vasher kind of hacked in order to imitate another magic system. Shardblades are organic parts of the world they are on, but Nightblood is a bunch of souls stuffed into something. Nightblood is like a Frankenstein.
Commentary : I think this provides insight into why objects that are more inhuman necessitate an increased amount of Breaths to Awaken. If the natural state of a Breath is to be attached to a human being, then perhaps all Awakening is creating a ‘Frankenstein”. Also, “imitate” denotes Vasher being cosmere-aware when Nightblood was created. Perhaps he worldhopped before the events of Warbreaker.
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