The Sword Tomb’s Blade Feeder

Chen Sui was sold to Sunken Sword Mountain to serve as a mute servant. He has just one duty: feed the sword a mouthful of blood each night and light every lamp in the tomb passage before dawn. After drinking blood, the sword gives up someone else's secret. The sect says these swords are the remains of their ancestors. On the seventh night, Chen Sui discovers that every secret the sword reveals is about how to kill the sect's current leader.