An Unexpected Party

"I am so sorry to keep you waiting!" he was going to say, when he saw that it was not Gandalf at all. It was a dwarf with a blue beard tucked into a golden belt, and very bright eyes under his dark-green hood. As soon as the door was opened, he pushed inside, just as if he had been expected. He hung his hooded cloak on the nearest peg, and "Dwalin at your service!" he said with a low bow.

Normal sudoku rules apply.

Thirteen dwarves are located around the grid (their names are shown). Being short of stature, they must all be from the set of digits {3, 4, 5}.

Digits in cages do not repeat, and must sum to the given value.

Cells a chess knight's move apart cannot contain the same digit.

The grid is partially covered in fog. Placing a correct digit will clear some of the surrounding fog, possibly revealing more clues.