Arlock is a villain in Fairy Tail and the main antagonist of the Avatar Arc. He is the high priest of the Avatar cult. He is voiced by Takashi Matsuyama (who previously portrayed Jose Porla) in the Japanese version of the anime and Chris Messersmith in the English version.
Arlock has the general body build of a middle-aged man, however, his true appearance is shrouded in mystery; the majority of his body is concealed by a black ferraiolo, in which his bears a pattern of insignias that resemble a lunate epsilon on its back. In particular, his ferraiolo is modified so that the collar circles around the back of his neck in a bowl-shaped fashion. From underneath the ferraiolo, a gorget can be seen jutting out, encircling Arlock's neck. Arlock's face is concealed by an ornate metallic mask that, around the mouth area, has engravings that resemble a beard and mustache. The mask possesses slits to allow respiration. The eyes of the mask have holes for Arlock to see, and the nose of the mask also has holes for him to breathe. To complete his outfit, Arlock wears, as typical of a religious figure, a mitre, his in particular stylized with the symbol of Avatar upon it, from under which his long, pinkish-grey hair flows neatly and rests upon his shoulders.
Arlock's personality, for the most part, is shrouded, much like his true face, in mystery. However, the amount of personal self he has displayed is typical of that of a cult leader; he reinforces the ideologies of his cult (in this case, the attainment of Zeref's ideal world and the destruction of those who oppose it) to its members, and appears to command a great deal of respect from his subordinates due to his position as priest. Underneath, however, he has a more malicious character; one, that is willing to sacrifice his underlings just to bring Zeref to him.
Arlock appears inside the Avatar building, convening with the members of the cult. Noting that the Balam Alliance's collapse brought the end to the era of the Dark Guilds, he proclaims Avatar to be a successor to the Dark Guild pact and vows to conquer the world in the name of Zeref by eliminating every Mage that does not pledge loyalty to the Black Mage.
After the meeting, Arlock goes to his private chambers and begins praying for their purification plan, however, he is interrupted by Jerome and Briar, who claim that the Council is aware of their plan and that they may have a spy in their midst. Arlock then, angered that they have interrupted his prayers, demands that they leave at once.