"Yog" is a title given to practicioners of corrupted arts whom reached to the point where they have become the corruption.
Cleric : "It is over Arnold! Surrender to the chur-"
Arnold : "For the last Frankensteining time it is YOG Arnold!"
Paladin 1:"Do you remember the kid in cultist robes that escaped from that raid? I heard he is a Yog now"
Paladin 2: "I wouldn't be suprised, I saw him eat pizza with pineapple"