Questioner (paraphrased)
Why do the Shardblades in The Stormlight Archive have the effect on flesh (human tissue) that they do?
Brandon Sanderson (paraphrased)
He originally wrote the scene in the prologue with the assassin Szeth using a traditional sword, but it was so bloody and gruesome that Brandon was actually disgusted. He had to find a way to avoid that and so he came up with a new way for the swords to behave.