Fire Seldom Dies Alone
Tome Hint - Black Crag: Discover a unique weapon or item and use it against this type of creature.
Order
Black Crag @ 38.5,45. Right click Crate of Torches to receive Torch.
Use torch (just once) on a dryad in the zone and kill it normally after. Each kill give you "Dryad Ash" (bound to player). Collect 10 of them and return to NPC "Godor Bronzmug" where you got the torch. There are 10 shots in a torch, so you can complete it with just 1 torch.
Destruction
Was fixed in patch 1.4.7
Black Crag @ 21.5,36. Right click Crate of Torches to receive Torch.
Use torch (just once) on a dryad in the zone and kill it normally after. Each kill give you "Dryad Ash" (bound to player). Collect 10 of them and return to NPC "Snotgul" where you got the torch. There are 10 shots in a torch, so you can complete it with just 1 torch.