The Evil One, as he is shown in the Bible.
The Bible of Omega IV was a religious text sacred to the Yangs, similar to their holy words.
Books of this Bible include Haggai, which has at least two chapters. A painting of the Evil One was placed opposite the page featuring the book of Haggai.
In 2268, the Yang Scholar showed Cloud William the Bible, which was his proof that Spock was the Evil One. (TOS: "The Omega Glory") Template:ReligiousTexts