Smaug

"The King under the Mountain is dead and where are his kin that dare seek revenge? Girion Lord of Dale is dead, and I have eaten his people like a wolf among sheep, and where are his sons' sons that dare approach me? I kill where I wish and none dare resist. I laid low the warriors of old and their like is not in the world today. Then I was but young and tender. Now I am old and strong, strong, strong, Thief in the Shadows! My armour is like tenfold shields, my teeth are swords, my claws spears, the shock of my tail a thunderbolt, my wings a hurricane, and my breath death!"

- Smaug "I am fire, I am...death!"

- Smaug Smaug aka Smaug the Dragon is the main antagonist of the 1937 classic novel The Hobbit by J.R.R. Tolkien and it's many adaptations. He appears as one of three main villains in Peter Jackson's live-action film trilogy of The Hobbit 2012-2014.

He is voiced and portrayed by Benedict Cumberbatch, who also played Khan from Star Trek: Into Darkness, the Necromancer and William Prince Ford from 12 Years a Slave.

The Hobbit
One of the last great dragons of Middle-earth, Smaug rose to prominence by laying waste to the town of Dale and capturing the Lonely Mountain (Erebor) with all of its treasure. He was already centuries old at the time, this having happened over 200 years before the events of The Hobbit. The book recounts the tale of a party of dwarves (consisting of a few of the original residents of the Lonely Mountain and their descendants) and the titular hobbit to recapture the mountain and kill the dragon. In the book, he is sometimes called Smaug the Golden, Smaug the Terrible and Smaug the Magnificent.

Smaug was intimately familiar with every last item within his hoard, and instantly noticed the theft of a relatively inconsequential cup by Bilbo Baggins. According to Tolkien, his rage was the kind which "is only seen when rich folk that have more than they can enjoy lose something they have long had but never before used or wanted." This theft and the dragon's ensuing rampage all echo the story of Beowulf, on which Tolkien was a noted expert and which he described as one of his "most valued sources" for The Hobbit. Among the items in Smaug's possession were the Arkenstone, and a number of mithril mail shirts, one of which was given as a gift to Bilbo by Thorin Oakenshield, the company's leader. In The Lord of the Rings, set 60 years later, the shirt saved Bilbo's relative Frodo from injury multiple times.

Smaug's belly was crusted in gems and gold, which rendered him almost invulnerable. However, when Bilbo met him in his lair, he discovered a bare patch on his left breast. When Bilbo told his Dwarf companions about Smaug's weakness, he was overheard by the thrush that roosted by the mountain's secret door. The thrush in turn told Bard the Bowman of Esgaroth. When Smaug attacked the town, Bard shot his Black Arrow into Smaug's left breast, the dragon's weak spot, slaying Smaug and causing him to plunge into Esgaroth.

After death
After Smaug's death, Thorin and Company claimed the treasure as theirs by birthright. This created a conflict with Bard and the Elven king, Thranduil, of Mirkwood, who each wanted a portion of the gold as reimbursement for all the damage Smaug had caused their kingdoms over the years. Thorin refused to share the treasure as long as they stood in arms before his gate, and declared war on both of them.

Conflict was avoided by the arrival of the Goblin and Warg army who wanted the treasure out of greed, and the Dwarves decided to ally with the Elves and Men to fight this greater evil in what was known as the Battle of Five Armies. The huge battle was eventually won by the Elves, Men and Dwarves, but Thorin was mortally wounded.

The Hobbit (1977 animated film adaption)
In the 1977 Rankin/Bass cartoon movie adaptation of The Hobbit, Smaug is voiced by Richard Boone. In this version, he resembles an Eastern dragon and looks more cat-like in appearance rather than a European dragon.

In Peter Jackson's films
Smaug also naturally appears in Peter Jackson's The Hobbit film trilogy 2012-2014.

The Hobbit: An Unexpected Journey
Although he doesn't appear much in the first movie, at the beginning of the film, Smaug's story is told and at the end of the movie, he is seen awakening. Smaug is kept either in shadow or never in full body view to keep his appearance a secret until The Desolation Of Smaug.

The Hobbit: The Desolation of Smaug
"Do you think flattery will keep you alive? No, indeed."

- Smaug to Bilbo Baggins upon their meeting.

When Bilbo Baggins is sent into the mountain alone, while the Dwarves are waiting outside and Gandalf is at Dol Guldur, Bilbo starts looking for the arkenstone, but accidentally wakes up Smaug, but before Smaug can spot him, Bilbo puts on the One Ring and hides from Smaug for a while, but Smaug says that he can detect a piece of gold that he carries and Bilbo eventually reveals himself.

Politely pretending to be an admirer, Bilbo flatters Smaug, but the dragon is aware of his true intentions. Smaug spoke of a darkness coming to their lands that preparing for war. Smaug revealed to Bilbo that he knew that he was sent to receive the arkenstone from Thorin and his company. Bilbo pretended that he knew nothing of what Smaug spoke of, which was pointless as Smaug knows that Bilbo intends to take the arkenstone.

After failing to win Bilbo's influence, Smaug boasts and as he does this, Bilbo locates a bare patch on his left breast. When Bilbo locates the arkenstone, Smaug reveals that he was secretly tempted to let Bilbo take it and let Thorin suffer the same fate as Thror did, as he too cares more about the gold and the Arkenstone more than others. But Smaug reconsidered and tries to kill Bilbo, but Bilbo once again hides by using the One Ring, causing Smaug to go off in a terrible fiery rage.

Smaug eventually finds Bilbo, Thorin and the rest of the dwarf company and attempts to burn them all, but they escape. Thorin eventually conjures up a plan to kill the beast and the dwarves lead him to the forges and trick him into lighting up the furnaces with his fiery breath, and after a long battle with the dragon, Thorin eventually confronts Smaug and reveals the giant golden dwarf statue, which was set up as a trap as the statue melted into gold and they attempted to drown Smaug in it.

Unfortunately for the dwarves, their strategy failed, as Smaug bursts out of the rivers of melted gold, shakes all of the gold off and flies towards Esgaroth, Lake-town, intending to destroy it for helping the Dwarves...

As Bilbo remains horrified at what they have unleashed, Smaug quotes "I am fire! I am...death!".

The Hobbit: The Battle of the Five Armies
Editing begins after December 2014.

LEGO: The Hobbit Video Game
In the 2014 Lego video game adaptation of the first two The Hobbit films, Smaug is naturally featured in it as well. He appears as a minifigure and will appear offically in his dragon form in a Lego Hobbit set later this October.

Quotes
"I am fire! I am...death!"

"DID YOU THINK I DID NOT KNOW THIS DAY WOULD COME?!! THAT A PACK OF CANTING DWARVES WOULD COME CRAWLING BACK TO THE MOUNTAIN?!!!"

"My teeth are swords, my claws are spears! My wings are a HURRICANE!"

"YOU think you could deceive me, Barrel-Rider?! You have come from Lake-town! This is some sort of scheme between these filthy Dwarves and those miserable tub-trading henchmen! Those sniveling cowards, with their Longbows and Black arrows! Perhaps it is time I paid them a visit!"

"So tell me, thief, how do you choose to die?"

"Come, now, don't be shy. Step into the light!"

"REVENGE?! REVENGE?!! I WILL SHOW YOU REVENGE!"

"I am King under the Mountain!"

"There you are, Thief in the Shadows!"

"The darkness is coming. It will spread to every corner of the land."

"YOU WILL ALL BURN!"

"You care about them, do you? Good. Then you can watch them die!"

"Don't bother denying it! I guessed his foul purpose some time ago."

"The king under the mountain is dead. I took his throne, I ate his people, like a wolf among sheep."

"I kill where I wish, when I wish."

"My armour is iron! No blade can pierce me!"

"You will take nothing from me, dwarf! I laid low your warriors of old. I instill terror in the hearts of men."

"Well, thief. I smell you. I hear your breath. I feel your air. Where are you? Where are you?!?"

"There is something about you. Something you carry; something made of gold. But far more..precious."

"You have nice manners, for a thief, and a LIAR!"

Trivia

 * Despite being a dragon, Smaug would technically be called a wyvern; a dragon has eight limbs - the head, the tail, four legs, and a pair of wings. Smaug however has six limbs, his head and tail, his rear legs, and his forelimbs doubling as his wings (which is how a wyvern looks) but both dragons and wyverns can breathe fire.
 * In An Unexpected Journey, Smaug is clearly has four legs while in The Desolation of Smaug, Smaug is more Wyvern-like in appearance.