Chung K'uei, The Demon Chaser

About the apotropaic figure in the picture below, Derk Bodde translates from Tun Li-Chen's Yen-ching Sui-shih-chi:

Every year at the time of Tuan Yang, shops have yellow streamers a foot long, covered with vermilion seal impressions, or perhaps painted with figures of the "Heavenly Master" or of Chung K'uei, or with the forms of the five poisonous creatures, which serve as charms. These are hung up and sold, and the people of the Capital [Peking] compete with one another in buying them. They are pasted on the second gate of one's house to ward off evil influences.

Derk Bodde then tells us the legend of Chung K'uei:

Once the T'ang Emperor, Ming Huang (712-756), while suffering from a fever, is said to have had a dream in which he was tormented by an imp. But suddenly a tall figure appeared which tore out the imp's eye and ate it. On being asked by the Emperor who he was, the figure replied that he was a physician who during a former reign had been unjustly defrauded of his rights in the government examinations. After this he had committed suicide, whereupon the Emperor of that time had ordered him to be buried with special honors. Out of gratitude he had then sworn ever to protect future rulers. On awakening, Ming Huang found his fever gone. He had the picture of his protector, Chung K'uei, painted, and canonized him with the title: "Great Spiritual Chaser of Demons for the Whole Empire."

Chung K'uei