The subject of this article originates from non-canonical sources. To find out about what is considered "canon" see LOTR:Canon.
Beginning of the BattleEdit
After Thorin and Company come out of the Lonely Mountain, Thorin and his best warriors (Dwalin, Fíli and Kíli) went to Ravenhill to kill Azog. Azog apparently ran from Ravenhill and Dwalin suggested that he escaped. But Thorin did not agree with Dwalin. He ordered Fili and Kili to go to the towers of Ravenhill and seek Azog. While Fili and Kili entered the caves unseen, a group of Goblin Mercenaries arrived and went on to engage Dwalin and Thorin. The goblins were easily defeated, but in Azog's command center (on one of the towers), Azog successfully captured Fili and impaled him with his Blade-Arm. Watching his nephew die, the body fell to the place where Kili was. Angered, Kili went to Azog's command center to avenge his brother's death while Thorin runs after him.
However, Kili was attacked by Gundabad Orcs led by Bolg. Legolas and Tauriel arrived and fought Bolg's forces. Tauriel was attacked by Bolg, but was saved by Kili who arrived and had a short duel with Bolg. But Bolg proved to be stronger and he managed to kill Kili with his Mace. An angered Tauriel threw Bolg to the lower levels of the mountain but she was dragged down with him.
Legolas VS BolgEdit
In the other side of Ravenhill, Legolas is shooting arrows at Orcs who are attacking Thorin. When he notices that Bolg is about to kill Tauriel, he attempts to shot Bolg, but he is out of arrows and he is forced to face Bolg with his sword . A Troll is trying to bring down the Tower were Legolas is shooting Orcs. Legolas jumps down onto the Troll and makes him hit the tower with great force. The tower falls near Bolg and the elf duels with him. A long duel between Legolas and Bolg ensues. On the frozen river, Thorin is fighting Orc Berserkers and their leader attempts to kill Thorin with his mace, but Thorin dodges and stabs the Orc in the neck with his broken sword. The Orc's dead body falls on the makeshift bridge and makes Bolg fall in the bridge's lower level where is trapped by multiple large rocks.
An Orc brute attempts to kill Thorin with an Axe. But Legolas saves Thorin by throwing Orcrist in the Orc's chest. Bolg escapes the bridge's lower level and attempts to hit Legolas with his mace. But Legolas dodges and Legolas unsheathes his short swords and attacks Bolg. Legolas and Bolg have a short duel which ends in Bolg's head being impaled by one of Legolas's short swords and his dead body falls off the mountain and is crushed by a falling boulder.
Thorin VS AzogEdit
Azog and Thorin furiously engage in a climactic sword duel until Azog drives Thorin on to the ice and ordering a series of his best troops to attack Thorin. Thorin desperately cuts through the Orcs and re-engages the Pale Orc. This time, Azog has abandoned his bladed weaponry and has equipped himself with an enormous chunk of stone on a great iron chain. Azog swings his Flail at Thorin and Thorin repeatedly dodges Azog's weapon. In the end Azog hits the Frozen River with his flail, locking the boulder in the ice. Azog looks at Thorin and and see behind him many Great Eagles led by Radagast and Gwaihir. Thorin picks the ball of the flail and gives it to Azog, The weight of the Orc and the flail causes the ice to break and Azog falls into the water. As Azog's body drifts away, Thorin follows it and falls for the Orc's trap. Using his blade arm, Azog stabs Thorin's foot and breaks through the ice and impales Thorin using his blade arm. However Thorin, whilst being pinned down then impales the Defiler with Orcrist and then flips him over and impales him again, but this time pushing Orcist even deeper into the Defiler's torso, forcing the sword to penetrate straight through the icy surface causing the Orc to stabbed onto the ice, a few seconds later the Defiler then dies, whilst looking into the eyes of his greatest foe.
The Great Eagles arrival was essential to the Elves, Men and Dwarves victory. Because a Gunabad Orc Army arrived at Ravenhill, Azog's plan was to make Thorin and his allies go to Ravenhill and then the Gundabad Army would kill them, but the Gundabad Army was crushed by the Great Eagles, Radagast, and by Beorn (on his bear form).