Durin

Warning: Wikipedia contains spoilers

Durin the Deathless was the first of the Seven Fathers of the Dwarves, who was set to sleep beneath the mountains of Middle-earth until the Elves were born.

Upon his awakening, he traveled until he came upon the Mirrormere, the lake that the Dwarves call Kheled-zâram. He created there a great city within the Misty Mountains. This was Khazad-dûm, later called Moria.

Durin founded the line of Dwarves called Durin's Folk, the inhabitants of Khazad-dûm. Although he was called the Deathless, for his long life, he was not immortal, and died during the First Age.