Runvastr is a poor dwarf that lives on Keldagrim's east side in the house directly south of the pickaxe shop. Despite his long years of work, he has achieved little and lives in a very small home. Not much else is known about him.
After completing the Love Story quest, you may speak with him about his days as a miner, after which you are given his diary from when he was a miner. Present this to the Wise Old Man in his house in Draynor and you are given the option to make tele-tabs to Trollheim.