Yūrei Samurai series, is based on the character Shūkō Narsus who appears in the Master Shǒuwèi series. Narsus is a famous actor and storyteller who plays the roll of the Masked Samurai in the Wandering Samurai series. This is one of his stories:

There was once a legendary Samurai who was known for his noble deeds far and wide. There was nothing he would do to help the people. However, there was also a dark side to these tales, that he could wipe out an entire army in a single night, without being spotted. A powerful clan leader sends out his men to find this legendary assassin for a task he knows no one would dare take on. 

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