Tainted Soul [WDP]

You have successfully survived reading the Book of Vile Darkness. As such this character has obtained the following permanent effects. 

Ability Score Adjustment
After you spend the requisite amount of time reading and studying the book, one ability score of your choice increases by 2, to a maximum of 24. Another ability score of your choice decreases by 2, to a minimum of 3. The Book of Vile Darkness can’t adjust your ability scores again.

Mark of Darkness
You acquire a physical disfigurement as a hideous sign of your devotion to vile darkness. An evil rune might appear on your face, your eyes might become glossy black, or horns might sprout from your forehead. Or you might become wizened and hideous, lose all facial features, gain a forked tongue, or some other feature the Player chooses.

The mark of darkness grants you advantage on Charisma (Persuasion) checks made to interact with evil creatures and Charisma (Intimidation) checks made to interact with non-evil creatures.

Dark Speech
You can use an action to speak words in a foul language known as Dark Speech. Each time you do so, you take 1d12 psychic damage, and each non-evil creature within 15 feet of you takes 3d6 psychic damage. In addition, you also know how to read, speak and write in Dark Speech, gaining advantage on further attempts to read from the Book of Vile Darkness.