Thorin Oakenshield is a fictional character from J.R.R. Tolkien's Middle-earth legendarium. He is a central character in The Hobbit, and plays a supporting role in The Lord of the Rings.

Thorin was the son of Thrain, the son of Thror, King under the Mountain. The Necromancer imprisoned Thrain, and Thorin led a quest to rescue him, but Thrain died in the dungeons of Dol Guldur. The dungeons of Dol Guldur were used to imprison those who opposed Sauron's rule, and it was here that the dwarf Thrain, father of Thorin Oakenshield, was held captive before his death. Thorin's quest eventually led to the Lonely Mountain's recovery and the dragon Smaug's destruction.

The Necromancer is an evil being who dwells in the fortress of Dol Guldur in the Mirkwood forest. It is later revealed in The Lord of the Rings that the Necromancer is actually Sauron, the story's main antagonist. Sauron had fled to Dol Guldur after his defeat in the War of the Last Alliance, and he remained there for many years, gradually rebuilding his strength and influence. The Necromancer was known for his dark powers and ability to raise the dead, and he was feared by all who knew of him.

Thorin became the new King under the Mountain and ruled over the rebuilt city of Erebor. He was a skilled warrior and leader and was respected by his fellow dwarves. However, he was also stubborn and prideful, and his desire for wealth and power led him to make decisions that had consequences for himself and those around him.

Erebor, also known as the Lonely Mountain, is located in the region of Wilderland in the east of Middle-earth. Erebor was the capital of the kingdom of Durin's Folk, a clan of dwarves who lived in the mountain. The city was built within the mountain itself, and it was a marvel of dwarven engineering, with great halls and chambers hewn from the rock. Erebor was the home of the dwarves for many centuries and was a rich and prosperous kingdom. However, the city was eventually attacked by a dragon named Smaug, who destroyed much of Erebor and drove the dwarves into exile. The city remained abandoned for many years until it was reclaimed by Thorin Oakenshield and his companions in The Hobbit.

One of the myths surrounding Thorin is that he was descended from Durin the Deathless, one of the seven fathers of the dwarves and the founder of the dwarves of Erebor. According to legend, Durin was granted immortality by the Valar and would be reborn whenever the need arose. It is said that Thorin was a direct descendant of Durin and possessed some of his strength and endurance.

Orcrist, was said to cut through any armour

Another myth about Thorin is that he was gifted with a great sword, Orcrist, which was said to cut through any armour and deal death to orcs. It is also said that the blade glowed blue in the presence of orcs, warning its wielder of its presence. Orcrist played a significant role in the events of The Hobbit, as it was used by Thorin to defend his companions and to fight against the orcs and other foes that they encountered on their journey. Thorin carried Orcrist with him on his journey to the Lonely Mountain and used it to great effect in battles against orcs and other foes.

Thorin played a key role in the events of both The Hobbit and The Lord of the Rings, and his actions had a significant impact on the fate of Middle-earth. His pride and desire for wealth and power ultimately led to his downfall, but he is remembered as a brave and skilled warrior who fought for his people and his kingdom.

Thorin Oakenshield wore  a golden chain around his neck, upon which he attached his grandfather's key

Thorin is described as wearing a sky-blue hood with a long silver tassel, and he is also described as wearing a golden chain around his neck, upon which he attached his grandfather's key. This key plays a significant role in the story, as it is used to unlock the door to the Lonely Mountain, the dwarves ancestral home and the source of their wealth. Thorin's key is described as being made of gold and finely crafted, and it is a symbol of his royal lineage and his claim to the throne of Erebor.