Born around 200 years ago in one of the refuges in the Iron Hills, years after the dragon Smaug had driven his kin away from Erebor, he nowadays nevertheless considers himself a dwarf of the Lonely Mountain. He is part of a Dwarven family of warriors and guardsmen, whose history goes all the way back to Khazad-Dûm. Since a child he grew up hearing stories of old and, in the end, being like his father, Dunnok and their forefathers.

He became skilled in arms and so far his greatest moment in warfare was to be with his father in the Battle of Five Armies after the dragon had perished. After their victory the Dwarves resettled back to their old home, rebuilding what the Dragon had spoiled. Some time later Gungur and his dear wife were blessed with children.

Many years he lived peacefully in Erebor crafting weapons of great skill and beauty, travelling every now and then selling his craft. When needed he served in his King's troops, as a guardsman and a warrior. Years later, upon one of his many travels, he and a group of fellow dwarves were ambushed by Dourhands. After several misfortunes and hardships during the time under the Dourhands' cruel treatment, working in forced labour mining and crafting weapons for their foul use, he and a few of his companions managed to escape. Scarred and bruised, but he was free once more. Forever spiting those who did him wrong, but free.      

He later returned to his home in Erebor, receiving grim news about the passing of his wife during his absence. After paying his respects to her stone tomb, he was all alone with his children, accompanied with his now old father. In great grief, anger and confusion he drove his son away from home, never to see him again, and marred the relationship with his daughter. Feeling himself a failed parent, he has mostly been focusing on his work, travelling and selling his handcraft east and west of the Misty Mountains.