Confirmation of Sauron’s return – Difference of the Movie and the novel
In the novel The Hobbit, Gandalf already confirmed the return of Sauron at Dol Guldur at this timepoint and Gandalf feared that Sauron might ally with Smaug.
So, in the novel, Gandalf suggested Thorin Oakenshield to take back Erebor because he wanted to eliminate Smaug before Smaug could join the forces of Sauron. In the novel, the nazguls including the Witch-king of Angmar were never captured nor buried.
However, in the movie The Hobbit, the White Council nor Gandalf haven’t confirmed the return of Sauron yet and the nazguls were also set as banished from Middle Earth.
In the movie, the nazguls especially the Witch-king of Angmar is described to be sealed in the deep hills of Rhudaur.
White Council – Difference of the Movie and the novel
In the novel, the White Council already knew of Sauron’s return, yet Saruman disagrees with Gandalf’s demand to attack Dol Guldur as Saruman insisted that the One Ring was missing.
In both the novel and the movie The Hobbit, Saruman desired the One Ring but hid his intentions so Saruman would constantly deny the return of Sauron and object to the attack on Dol Guldur.
Also, the White Council in the novel wouldn’t discuss of the return of the Witch-King of Angmar as the nazguls were never caught nor buried in the novel.
In the movie The Hobbit, Gandalf would present the Morgul Blade, the sword of the Witch-king of Angmar to the White Council.
The White Council from the cinema would also explain that the nazguls were all buried deep in the hills of Rhudaur after the war against the evil kingdom.
The evil kingdom would refer to Angmar and by the movie settings, the nazguls were all buried and sealed by magic.
The movie might have changed the setting to avoid the complication of the old history of the Angmar Wars and the complicated politics of Saruman who desired the One Ring between Sauron.
Dol Guldur – Strategic Point of Sauron
Dol Guldur means The Hill of Sorcery and it was a fortress of the dark forces that Sauron would hide and occupy until the end of the War of the Rings.
After 1,000 years since Sauron lost to the Last Alliance of Elves and Men and his physical body perished from Middle Earth, Sauron’s weak soul took place in Dol Guldur.
Dol Guldur was originally called Amon Lane that watched over the south of Greenwood the Great. Mirkwoods was once called Greenwood the Great, however as Sauron started to dwell and recover slowly at Dol Guldur, Sauron caused darkness in the south of Greenwood the Great.
The darkness caused by Sauron would lure dark creatures like the giant spiders in the south of Greenwood the Great and eventually the darkness swallowed Greenwoods and Greenwoods became the Mirkwoods.
Thranduil couldn’t hold the south of the old Greenwoods which would now be called Mirkwoods and the elves would retreat further north of the Mirkwoods.
In the movie, Gandalf explains that Dol Guldur was a strategic point that could link Mordor with the old, perished kingdom of Angmar, Gundabad that was in the north of the Misty Mountains and Moria.
In the novels The Hobbit and the Lord of the Ring series, similarly Dol Guldur was an important forward base for Sauron.
Hills of Rhudaur
In the novel The Hobbit or the Lord of the Rings and the original Legendarium, the nazguls and the witch king of Angmar were never sealed by magic and they would only perish with the One Ring and Sauron.
However, the cinematic series couldn’t explain the complicated history of the diversification of Arnor nor the history of Angmar so it set that the nazguls were defeated and buried in the hills of Rhudaur.
Rhudaur isn’t a location but originally it was a kingdom that diverged from the Northern Kingdom Arnor.
Arnor, once the kingdom of the Dunedains diverged into three kingdoms Arthedain, Rhudaur and Cardolan.
The movie The Hobbit An Unexpected Journey would set that the nazguls were defeated during the Angmar wars and they were buried in the underground of the hills of Rhudaur.
Among the three kingdoms, Rhudaur was located at the northeast and the closest to Angmar where it was located north of the three kingdoms of Arnor.
Angmar and the Witch king of Angmar and Gundabad
The Witch-king of Angmar founded the evil kingdom Angmar at the north of Arnor to eliminate the bloodline of Isildur and the three kingdoms that descended from Arnor.
The Witchking of Angmar was responsible for the fall of Rhudaur, Arthedain and Cardolan thus the Northern kingdoms of the Dunedain.
The Witch-king of Angmar also thought he successfully cut off the blood line of Isildur, however the bloodline of Isildur survived and the heir of Isildur Aragorn would return as the king of Gondor and Arnor later.
Just one year after the fall of the kingdoms of Arnor, Angmar lost the Angmar War against the elf and Gondor alliance.
In the original stories of the Legendarium, the Witch-king of Angmar flees to the east and not all of the nazguls took place in the Angmar wars.
However in the movie, the complicated history of the Angmar Wars were all compressed to a setting that the nazguls and the Witch-king of Angmar were captured by the Gondor-elf alliance and sealed in the hills of Rhudaur.
Gundabad was also part of the old Angmar kingdom and both the novel and the movie, the remnants of the Angmar realm fled to Gundabad.
Morgul Blade / Morgul-Knife
There aren’t many original descriptions of the Morgul Blade or the Morgul-Knife by J.R.R. Tolkien and Christopher Tolkien.
However, the Morgul-Knife was one of the blades that the Witch-King of Angmar possessed.
Morgul means ‘magic’ or ‘sorcery’ so possibly the Morgul-Knife might mean a blade or knife with magic or it may be an item to indicate the Lord of Minas Morgul the Witch-king of Angmar but not much is known of its origin.
The Morgul Blade would weaken the being that was stabbed by it and eventually the stabbed being would become possessed by the dark magic of the Witch-King of Angmar.
Frodo Baggins was stabbed by the Morgul-Knife at rubbles of Weathertop(Amon Sul) during Lord of the Rings: Fellowship of the Rings. Frodo Baggins would eventually suffer from the wounds and magic caused by the Morgul Blade.
In the movie The Hobbit, Gandalf presents the Morgul Blade as proof that the nazguls have returned to Middle Earth and Gandalf would imply that the master of the nazguls Sauron may have also returned. Gandalf tried to convince the White Council that the necromancer known as human at Dol Guldur might be Sauron during The Hobbit An Unexpected Journey.
