Officially announced by Peter Jackson on his facebook page, Azog is described simply as an Orc. [Click here] Peter Jackson will be referring to the ‘goblins’ in book The Hobbit as ‘Orcs’ in the film.
King of the Orcs of Moria, Azog is described in Appendix A of Lord of the Rings as “a great Orc with a huge iron-clad head, and yet agile and strong.” Azog’s murder of Thror in the year Third Age 2790, the subsequent defilement of the body and his scornful words to the dwarf’s servant, Nar, sparked the brutal Dwarf-Orc wars that raged the length of the Misty Mountains for six bloody years. The revenge of Durin’s Folk was completed in the Battle of Azanulbizar (or Nanduhirion in Sindarin) in TA2799 when the forces of Azog were finally brought to bay in the valley before the east gates of Moria — a battle of which the memory still makes Orcs shudder and Dwarves weep.
Thrain II lost an eye, while Thorin gained the name “Oakenshield” when he took up a branch of oak as a defense after his shield was shattered. But, it was a young Dain Ironfoot who took vengeance upon Azog, slaying him before the very doors of Moria itself. Azog’s son Bolg was the commander of the Goblin forces many years later at the Battle of the Five Armies.
In “The Hobbit: An Unexpected Journey, we see the battle of Anazulbizar in a flashback narrated by Balin. Azog, a giant white orc known as, “The Defiler,” beheads Thror, but instead of being killed by Thorin, Thorin cuts off his left forearm and Azog is dragged back into Moria by his orcs, seemingly with a mortal wound. Soon after, we learn that Azog survived and is now leading a band of orcs in pursuit of Thorin and company to get revenge on Thorin for cutting off his arm and defeating his forces in the battle. His forearm and hand have been replaced with a forked metal weapon that’s been thrust through his forearm and he rides a gigantic white warg.
At the end of AUJ, Thorin and company barely escape being cornered by Azog and his orcs, and Azog is enraged when they’re carried off at the last minute by the Eagles. In “The Hobbit: The Desolation of Smaug,” Azog continues his pursuit of Thorin and company until his son Bolg, informs him that the Necromancer has summoned him to come to Dol Guldur to lead the forces he’s gathered there. Azog sends Bolg in pursuit of Thorin instead.
As with many of the orcs in the Hobbit movies, the orc Azog was switched from being an actor wearing prosthetics to completely CGI mid-way through filming. Azog’s movements and facial expressions were all filmed via motion capture using the actor who portrays him: Manu Bennett. Manu also suggested to Peter Jackson that Azog have a connection to his white warg, thus he can be seen petting the animal in AUJ and the warg nuzzling him in return.
‘If beggars will not wait at the door, but sneak in to try thieving, that is what we do to them. If any of your people poke their foul beards in here again, they will fare the same. Go and tell them so! But if his family wish to know who is now king here, the name is written on his face. I wrote it! I killed him! I am the master! ‘Then Nar turned the head and saw branded on the brow in Dwarf-runes so that he could read it the name AZOG. That name was branded in his heart and in the hearts of all the Dwarves afterwards. — Source: The Lord of the Rings: Appendix A