Bombur was a Dwarf who accompanied Thorin Oakenshield and Bilbo Baggins on their journey to the Lonely Mountain. His brother Bofur and cousin Bifur also were part of the company. Bombur was by far the fattest Dwarf in the company.
Bombur's parentage is unknown; the only familial connections mentioned are his brother Bofur and his cousin Bifur. Bombur was not of Durin's line although he was descended from Dwarves of Moria. His birth year is also unknown, however, from Bilbo Baggins' account from the quest to Erebor it is known that the brothers Fíli and Kíli were the youngest of the 13 "by some fifty years" and that after Thorin had been captured, Balin was "the eldest left". Since Fíli was born in TA 2859 and Balin was born in TA 2763, this would put Bombur's birth between 2763 and 2809, and he would have been between 132 and 178 years old during the quest to Erebor. Prior to the quest Bombur probably lived in the Blue Mountains with Thorin after the loss of Thráin II.
Bombur was the twelfth Dwarf to arrive at Bag End for the meeting arranged by Gandalf, which became the outset of the Quest of Erebor. Because he was commonly considered to count for two dwarves on account of his girth, he was the last to arrive at Beorn's house and the last to cross the Enchanted stream in Mirkwood. Bombur was first introduced when he tumbled with Bifur and Bofur onto Thorin when they entered Bag End. He chose to stay and guard the camp and supplies while the others moved up the Lonely Mountain because he trusted neither mountain paths nor ropes to stay intact under his weight. Later though, he was forced to use the ropes to escape the rampaging dragon Smaug before he could be slain.
Bombur fell asleep at several key moments during the journey to the Lonely Mountain; when he is violently knocked into the Mirkwood River by an aggressive stag, he falls under a spell that makes him sleep for days, burdening the others with his weight as they walked on. While he is on a midnight lookout in the fortified Lonely Mountain, Bilbo promises to keep watch so that he can sleep a bit longer and take another watch later (Bilbo used this opportunity to sneak the Arkenstone out of the mountain and to give it to the Elvenking and Bard the Bowman). Incidentally, he was asleep when they opened his barrel after escaping the Elves of Mirkwood and also when Bilbo discovered the secret entrance to Lonely Mountain. Bombur is always last and doesn't enjoy it, for he usually comes on his own (due to his girth making most count him for two dwarves). When the Dwarves, Gandalf, and Bilbo meet Beorn, Bombur comes last at the request of Gandalf, coming along right after Bifur and Bofur leave him behind and head to Beorn's house (Instead of waiting the five minutes as he was instructed to by Gandalf). He fought and survived along with most of the company at the Battle of the Five Armies. Following the defeat of Smaug, Dain II Ironfoot gave him his share of the treasure and he remained to live at the Lonely Mountain until the end of his days.
In The Lord of the Rings, many years later, Frodo Baggins inquires after Bombur and learns from Glóin that he has grown so fat it takes several Dwarves to lift him to the dinner table. It is unlikely that Bombur fought in the Battle of Dale due to his obesity.
n Peter Jackson's Hobbit film trilogy, Bombur can be seen using a number of different weapons and tools to fight off enemies. His primary weapon is an iron ladle, which he wields during An Unexpected Journey. He also uses a cleaver or butcher's knife to slash enemies. In The Desolation of Smaug, he uses the same weapons but usually wields an axe. Of course, his greatest weapon is his size which he uses to crush and bounce away opponents. Bombur and his family are not classically trained fighters but are lethal with any sort of tool in their hands.
He also is surprisingly agile for a dwarf of his size and weight. He is very capable of performing stunts such as when, in the second film, he pole vaults into a barrel. He has an astonishing degree of durability, and can withstand a hard landing on a great number of Orcs, and also absorbs an incredible amount of momentum in the process, without breaking a limb or causing himself any visible degree of injury. In addition, he is a quick thinker and uses his ingenuity frequently to help push past Orcs or leap across gaps.
In Peter Jackson's live-action The Hobbit films, he was portrayed by Stephen Hunter. In 2012, the studio released the following statement about Bombur in the upcoming trilogy:
Brother to Bofur and cousin to Bifur, Bombur is the chief cook amongst The Company of Dwarves. His immense size and voracious appetite causes frequent problems – and laughter – for himself and The Traveling Party. Despite his size he can be surprisingly effective as a fighter – and woe betide anyone who makes him late for dinner!
Unlike in the book, Bombur appears less frequently and has virtually no dialogue in the films other than grunts or retorts. In the extended edition of the third film, he speaks after the axe in Bifur's head is removed. Throughout the films he is largely a source of comic relief, most of which pertains to his size and love of eating; such as catching food in midair, being able to outrun his fellow Dwarves despite his girth, exceptional fighting skills, even under duress, breaking a table under his own weight with the addition of merely an ounce of food in his hand.