After arriving at Don Guldur to free Gandalf, Galadriel is confronted by Sauron. Thinking she is the “only light in the darkness”, The Nine Ringwraiths (Nazgûl) surround her and Gandalf. But Elrond and Saruman arrive to assist their Lady.
“You have no power here, servant of Morgoth! You are nameless, faceless, formless. Go back to the void from whence you came!”
The Attack on Dol Guldur appears in the 2nd Hobbit movie by Peter Jackson and features as one of the main plotlines, besides Smaug’s attack to Lake-town and the gathering for battle at the Lonely Mountain. After Gandalf was defeated and captured after facing Sauron in The Desolation of Smaug, the White Council (Galadriel, Saruman, Elrond, and Radagast the Brown) is determined to come to his aid and face Sauron/The Necromancer and The Nine (Nazgûl).
Gandalf is seen suffering in his prison cage and attempting to mutter a spell with Radagast also chanting spells in Rhosgobel to support his fellow wizard. An Orc chieftain scorns the wizard for using spells in his master’s domain, he roughly tosses Gandalf out of his cage and demands to know the whereabouts of the Ring of Fire, which Sauron is somehow aware of. Gandalf lashes the Orc in the mouth with a chain. Unfazed, the Orc examines Gandalf’s hand and discovers Narya. The Orc prepares to cut it off, but some other power stops him in his tracks.
Galadriel emerges and commands the Orc to stand down or else be destroyed. When he roars in defiance, Galadriel raises her arm and unleashes a deadly light that dissolves the Orc and rents the sky for miles. She bears Gandalf away in her arms, and Sauron calls out to her in Black Speech. He specifically chants the verse referring to the rings of power, which Galadriel finishes in the Westron “Nine for mortal men doomed to die”. She and the unconscious Gandalf are surrounded by the spectral forms of the Ringwraiths/Nazgûl.
In the books by J.R.R. Tolkien, not much is known of the actual battle. Nothing is mentioned about whether it was simply a duel between great powers, or if it involved the use of conventional weapons. Some facts are mentioned, however, that Sauron retreated before the Council due to the devices of Saruman, as stated by Gandalf. While Sauron was forced to fly to Mordor, his plan to rule Middle Earth had long been prepared, as he had anticipated that the White Council would eventually drive him out.
Both Gandalf and Saruman are Maiar, near-primordial spirits that descended into Arda to help the Valar first shape the World. Each of the Maiar is associated with one or more particular Vala, and were of similar stock, Curumo (known in Middle-earth as Saruman) belonged to Aulë the Smith. Others included Mairon (originally also of Aulë, known in Middle-earth as Sauron), Aiwendil (known in Middle-earth as Radagast) who belonged to Yavanna the Fruit-Giver, and Olórin (known by the Elves as Mithrandir but came to Middle-Earth as Gandalf) who belonged to Manwë the Wind-King and Varda the Star-Queen.
It’s not Gandalf or Saruman, however, who banishes Sauron in The Hobbit: The Battle of the Five Armies, it was Galadriel and the reasoning behind this would be the following. Gandalf and Saruman were sent to Middle-earth as Istari and were forbidden to seek dominions of their own — to use their power to get Men or Elves or Dwarves to serve them and name them lord. They were forbidden to try to defeat Sauron by matching their power against his directly. They were not allowed to set themselves up as his direct counterparts and engage him directly as the celestial beings that they really are. They were forbidden to reveal themselves as the beings of great power and majesty. This doesn’t mean that they could never use their powers, however.
Galadriel is the Lady of Lothlorien, granddaughter of Finwe the High King of the Noldor and one of the last elves (perhaps the last) in Middle Earth to have seen the light of the Two Trees. She survived through incredibly dangerous and destructive periods of history and wields Nenya, the Ring of Water. She is the most powerful elf in Middle Earth. Tolkien mentioned repeatedly that Feanor and Galadriel were the greatest Elves to ever exist in the history of Arda even over Elu Thingol, the husband of Melian the Maia. However, the power of Galadriel alone in “songs of power” is not enough to withstand even a weakened Sauron as the Necromancer according to Tolkien.
Galadriel is an incredibly powerful being and according to Tolkien, by the Third Age she is “equal to Feanor but wiser” she and Glorfindel are the last of the Eldar of Valinor left in Middle Earth. When Sauron appeared, Galadriel took on the transformation of a High Elf “revealed in his wrath” or in general high elves revealed in wrath which according to Tolkien, was an “immense” display of angelic power that the mightiest of the Eldar of Valinor could transform into.