Thráin II

"No. No. Thorin must not go near Erebor. No one must enter that mountain."

- Thrain to Gandalf

Thráin was a Dwarf of Middle-Earth and was also a Dwarf of Erebor.

Throughout his lifetime, Thráin was the heir to the kingdom of Erebor and the prince of Durin's Folk, ut never king under the mountain or king of Durin's Folk.

He was also the father

of Thorin Oakenshield, Frerin and Dís, son of Thrór, and the maternal grandfather of Fíli and Kíli and grandson of Dain the First. He was named after his ancestor, Thráin I.

A young dwarf, Thráin raised his children solely after his wife died and never remarried. However, he was not able to raise his children in the Mountain for long, for the Dragon Smaug had conquered the Lonely Mountain, leaving Thráin to fend for himself and for their people.

Sometime later, Thráin cam e to the Battle of Moria, where he witnessed the death of his father. He was last seen fighting off Azog, never returning to Thorin. For years, Thráin stayed in the fort, Dol Guldur. A century later, Thráin was found by Gandalf, the grey wizard who came looking for more trouble that came this evil fortress. However, Thráin was not able to escape with Gandalf, for the Necromancer confronted the duo and snatched Thráin, seemingly killing  him.

He was portrayed by Thomas Robins and Michael Mizrahi in An Unexpected Journey and Sir Antony Sher in The Desolation of Smaug.

Thráin II is a member of the Line of Durin and a Dwarf of Erebor

Imprisonment
Sometime after the Battle of Dol Guldur, Thráin was thrown into the dungeons of Dol Guldur, going through Torture, but never telling them anything. He knows that Sauron and Smaug are together, due to his imprisonment there. Throughout his imprisonment in the fortress Thráin grows mad, even forgetting his own family and his own name. He began hallucinating "serpents" were keeping him there, unaware they are vines.

Death
Gandalf and Thráin made their way through the fortress before they were intercepted by Azog, who attempted to capture the two of them. However, Gandalf with his magic blinded the Orc and made out with Thráin. However, the dwarf prince saw that there was no hope for him, and told Gandalf to tell his son that he loved him before the dwarf is taken by the Necromancer and killed.

Instead, this made Thorin the true king under the Mountain after his father's death.

Personality and traits
He did care for the safety of others. This is notable when he is in horror when he learned that Thorin and a company have gone to reclaim the Lonely Mountain from Smaug and claimed that no one must enter the mountain, also indirectly caring of what would happen to Thorin's burglar and companion Bilbo Baggins and their companions.

Weapons
Before his imprisonment Thrain wielded a dwarven hammer