Based on the 1977 cartoon with portrayals from the new movies.
Needless to say, I do not own anything related to The Hobbit, Lord of The Rings, any of J.R.R. Tolkien's works, or Peter Jackson's versions.
Warning: Tear-jerker
Farewell
Late in the evening, as the sun began to sink behind the Lonely Mountain, Bilbo Baggins awoke. Silence reigned around the halfling as he rubbed the lump at the back of his head. From his place at the crest of the hill, he could see absolute stillness across the field of battle. Bodies lay where they fell while death lingered in the air, and the Shireling thought wistfully of his companions, if any still survived.
Bombur came puffing over the hill, calling the hobbit's name and Bilbo waved and then remembered his magic ring. He quickly ducked behind a rock and removed the piece of jewelry before standing again, calling the cook's name. The portly dwarf hurried as quickly as he could to the hobbit before falling to his knees and wheezing.
"Bombur, you're hurt!"
"I still live. And you?"
"A slight wound, crack on the head. Out for hours. What happened?"
"We won." Bombur gave his last breath and fell still.
Only after staring silently for several moments did Bilbo realize that was the first time he had ever really heard the dwarf speak. If Bombur was gone, who else could possibly have survived the battle. Slowly, the hobbit placed the older dwarf's hands on his chest over his ill fitting armor and stood. Wandering through the tangled and bloody bodies, the Shireling came across Gandalf turning the dead, searching for survivors.
"Bombur gone." The wizard muttered to himself as he saw the burglar's approach.
"Of our original 13, how many are left?" Bilbo was glad at least that the old man had survived, even with his arm in a sling.
"Seven."
"And Thorin?" The halfling dreaded the answer, hoping against hope the king had survived, but bearing the pain of his betrayal near to his heart.
"Soon will be only six." Gandalf saw the pain pass over the hobbit and sighed. The small people of the west could love too fiercely and too completely, even at the expense of all logic as in Bilbo's case.
"Will he let me see him? One last time?"
The wizard nodded. "He is asking for you."
Bilbo didn't wait for anything else, sprinting away as quickly as his short legs could carry him over the uneven ground. His little heart pounded with loyalty and regret as he drew closer to the tent that housed the dwarf king. There was no doubt in his mind that the being he foolishly gave his heart to was close to leaving the world and the halfling would see him once more, even if it meant being accused of his original treachery again.
Gandalf appeared at the tent as the hobbit approached, leading the way into the dark interior. "I have brought him." Hesitantly, Bilbo neared the bed, afraid to look upon the battered form of his affection.
"Farewell, good thief. I wish to part in friendship and would take back my words at the gate." Thorin's voice was weak as he lifted his hand for the burglar's.
Grateful for his permission, the hobbit took the calloused dwarf hand carefully. "There are many words I would take back also."
"And does it take this, to make us see each other?"
"Thorin," There was much the halfling wished to say, but he could not find the words.
"Hush. You are no coward, my friend. I am sorry I so named you."
"This is not important."
"I was wrong. You did understand war. It was I who did not." Thorin's breath caught in his injured lungs and Bilbo could hear a wet crackling as he breathed. "Until now."
"Farewell, King Under the Mountain." Not blinking so he could fix every moment in his mind, the Shireling's eyes welled with tears. Regardless of his misplaced attempt to stop the war, he would never again look upon the older dwarf that had so quickly become entrenched in his heart.
"Child of the kindly west, I have come to know if more of us valued your ways, food and cheer above hoarded gold, it would be a merrier world." The halfling recognized the admission for what it was, as an apology, despite having forgiven him the moment the king deposited him on solid ground instead of dropping him off of the gate. "But sad or merry, I must leave it now. Farewell."
"Farewell, Thorin."
Nothing held back the tears as Balin pulled the blanket over the king's face and Dwalin laid Orcrist on his breast. Night had fallen completely but Bilbo could only sit beside the bed, stroking the cooling hand he still held. He forced away all thoughts of 'what if' and 'if only' before he could drive himself mad with false dreams. The hobbit relived every moment of the adventure, from Dwalin arriving on his doorstep and devouring his dinner to witnessing Smaug's magnificence first hand. With great care, the Shireling fixed the color of the king's blue-gray eyes in his mind and let go of the hand he had clung to. Never again would he look upon the true King Under the Mountain and he left the tent.
Before Dain could be crowned the new King Under the Mountain, Bilbo had packed his small bag, taking only two chests and the map, and left the great dwarf city. He could not bear to call another dwarf King while his heart's own lay cold in the earth. Gandalf caught up to his small pony at the edge of Mirkwood and silently rode beside the hobbit. They retraced their steps to Beorn's house and soon stood at the foot of the Misty Mountains. The Shireling kicked at the charred wood and stone where the eagles had rescued them until he stubbed his toe on a hefty piece. The wizard said nothing as Bilbo held the cracked and burned oaken shield Thorin had carried into battle close to his chest and wept.
At last they reached the Shire and Bilbo stared at the green door of Bag End as if he had never seen it before. It was only half a year since he had left, but as Gandalf had predicted, he was not the same hobbit. The wizard left eventually, and the halfling couldn't bring himself to clean away the mud smeared on his mother's glory box or the mess made of his larder for many weeks. Whispers began in Hobbiton, of halls packed with gold and the odd hobbit that cavorted with dwarves but he couldn't be bothered to care. Not when his heart was buried in Erebor with the Arkenstone.
Age slowly caught up to the hobbit, long after the memories of adventure had gone beyond all recall or desire. He clung to one memory as if his life depended on it, a dwarf with blue-gray eyes and a strong jaw, voice deep and commanding, as he strode to meet the armies threatening his home and his people. Even that last desperate memory began to fade, losing all color and form until nothing was left but a hole in his heart and a name dying on his lips in the west.
"Farewell Thorin, King Under the Mountain."