Kahz using Julchaga as a prop to teach Doriatessa is gold
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When the art makes those sword movements... it doesn't hold back, the "invisible cut" is something a lot of artists use to pass the idea of speed and cheat the art a little, but actually... it is really difficult to make it look cool.
There is a very subtle balance between the "invisibility" and the movements of the character that need to be achieved to make it really feel like enormous speed, if not, you immediately notice that it was only done because the artist didn't had any better idea.