Update 12/18/12: If you’ve seen the film you’ll know that Thráin plays a part in the flashbacks at Erebor, and Moria, but not quite in the same way as in the text. I won’t go into details yet, but rather say that the scene shown below of Gandalf fighting Thráin is not in film one.

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According to my web stats, I get more people searching for “Who is Gandalf fighting in the trailer?” than anything else! So, although this is only a hypothesis, the best guess is the scene shows a confrontation between the wizard and Thorin’s father, Thráin II, at Dol Guldur.

I’ve detailed my reasons for this here, but I wanted to take a moment to highlight the life of Thráin for those wondering who this grey ball of hair and fury may once have been (and if you think Thorin is a badass, wait till you read about his daddy!)

Born in 2644, the only son of King Thrór, Thráin II was destined never to claim the title King under the Mountain, though during much of his father’s reign, their kingdom was prosperous, and trade between the dwarves of Erebor and the men of Dale flourished. By the age of 126, Thráin had three children; two sons, Thorin and Frerin, and a daughter named Dis. By the time his youngest child was ten, Thráin’s world suffered a tragic upheaval when the dragon Smaug came to call. Many of their people were trapped in the mountain and killed, but Thrór and Thráin escaped via a secret passageway.

It is implied that the now homeless dwarves found no aid from men or elves in the aftermath of this disaster, though it is likely their allies in Dale were just as devastated. They journeyed south to Dunland, and did what they could to survive.  Gone were the days of wealth and glory, but Thráin’s father was not prepared to live like this forever. Taking one old companion named Nar, Thrór left his son and grandchildren, and returned to the gates of Khazad-dum (and to the impossible dream of reclaiming the ancestral home of Durin). He may have been a little mad by this point, but at least he possessed enough sense to pass along the secret heirlooms of his house to Thráin before leaving; a map of the Lonely Mountain, a key to the secret passageway, and the last of the Seven Rings of the dwarf-kings.

Thrór’s dream of reclaiming Khazad-dum turned quickly to nightmare, as he was met by orcs inside the mines.  Their leader, Azog, took great pleasure in his death. They tossed Thrór’s severed head to Nar, as a challenge to any who would dare enter the mines. Nar brought the news to Thráin, who brooded on it for seven days, until he could bear it no more.

Now as King of Durin’s Folk, it was Thráin’s right to call on dwarves from across the Seven Houses to aid him, and he spent years amassing an army for the express purpose of avenging the death of Thrór.

The orcs learned to regret their challenge to Durin’s heir, as over the next few years, Thráin and his army hunted them down without mercy. The final battle culminated where it all began; outside the gates of Khazad-dum, at the Battle of Azanulbizar.

Thráin led the charge against Azog’s forces, but he was blinded in one eye during the fight, and his son Frerin was killed.  A large percentage of the dwarf warriors gave their lives to avenge Thrór’s that day. Once Azog was killed, and the rest of the orcs decimated or scattered, Thráin believed their way to Khazad-dum lay unbarred.  He would have gone in to claim the ancient throne of Durin had not his army balked at going further. The cost of revenge had been too great, and the leaders of the other Houses believed their duty was fulfilled. Dain, his kinsman, forestalled his entry to Moria with the words “You are the father of our folk, and we have bled for you, and will again. But we will not enter Khazad-dum. You will not enter Khazad-dum. Only I have looked through the shadow of the Gate. Beyond the shadow it waits for you still: Durin’s Bane.” With little support, Thráin could do nothing but agree.  A dark day it must have been for him to have lost a son, while gaining nothing but a fruitless victory.

History records few of Thráin’s words, but standing next to the staked head of Azog, he speaks to his son Thorin: “Some would think this head dearly bought! At least we have given our kingdom for it. Will you come with me back to the anvil? Or will you beg your bread at proud doors?” Thorin answered, “To the anvil. The hammer will at least keep the arms strong, until they can wield sharper tools again.”

So they wandered across Eriador, until reaching the Blue Mountains in the far West. There were few riches to be found within those ranges, and it would be long before the people of Durin would again experience the prosperity they once enjoyed. Thráin’s mind wandered always toward reclaiming his birthright, but he withstood the pull of Erebor for nearly 40 years. At the age of 197, he set off on a secret journey with only a few companions, among whom were Dwalin and Balin. For whatever reason, he chose not to tell his son of his plan to return to the Lonely Mountain, but took the map and key, hoping for some turn of luck.

The Ring of the dwarf-lords, which had been given to him by Thrór, proved to be his undoing. Sauron, the Necromancer, had a hand in creating it long ago with the intention of enslaving the dwarves to his will, but having failed to achieve its intended purpose, he sought to reclaim it.

After long years, and a dangerous journey which led up to the edges of Mirkwood, Thráin was separated from his party, and taken prisoner by Sauron’s minions. His companions never knew of his fate until decades later, when they were informed by Gandalf during dinner at Bilbo’s house.

Thráin’s journey ended in the dungeons of Dol Guldur, the seat of Sauron’s power at the time. Once the Ring was taken from him, the dwarf was of no importance, and he was left to rot in the pits. There it was that Gandalf found him in a state of madness. But even so, something of his old determination must have lingered, since, despite forgetting his own name, and that of Thorin, he insisted the map and key be passed on to his son. But while Gandalf accepted this vague task, he did not have the power to save Thráin from his fate, and the dwarf died there, at the age of 206.

Thráin was proud and fearless, even for a dwarf, and his natural desire to return his people to their rightful place was likely heightened after procuring the last of the Seven Rings of power.  Like most of the dwarves, Tolkien took the name of Thráin from the Old Norse poem, the Völuspá. The verb thra means “to desire vehemently”, and within this context, his name means pertinacious or obstinate. He was aptly named.  Loath he was to give up Khazad-dum, and athough he attempted to adapt to exile, in the end, his restlessness drove him to return to Erebor.

The following is concept art for Thráin’s armor in the film.  From Weta Workshop’s The Hobbit: An Unexpected Journey: Chronicles: Art & Design

Sources:
-Tolkien, J.R.R. Appendix A of The Return of the King. New York: Ballantine, 1978.
-Tolkien, J.R.R.  The Hobbit.  Boston: Houghton Mifflin, 2007.
-The Elder Eddas of Saemund Sigfusson; and the Younger Eddas of Snorre Sturleson at Project Gutenberg, translated by Benjamin Thorpe (Elder Eddas) and I. A. Blackwell (Younger Eddas). (1906)