Devil painting

A painting of the Evil One from the Omegan Bible

The Evil One was a figure in mythology on the planet Omega IV and was viewed upon by the Yangs as an equivalent to the Human Devil of Christianity.

In 2268, Captain Ronald Tracey visited Omega IV and, in violation of the Prime Directive, sided with the Kohms in their war with the Yangs. After the Kohms were defeated, Tracey was captured by the Yangs and attempted to persuade them that he was a representative of God and that Captain James Kirk and his party was servants of the Evil One. As proof of this, Tracey pointed out that Commander Spock looked exactly like the Evil One as depicted in the Yang's version of the Bible.

After a fight to the death where Kirk spared Tracey's life, the Yangs released all the Starfleet personnel and proclaimed Kirk "Great God's Servant". Kirk promptly informed the Yangs that he and his fellow Humans were not gods or evil ones, but simply mortal men. (TOS: "The Omega Glory")