Quite important quest, as you can't progress further in the chain.
The quest is The Drakkensryd,
the LOS with drakes and usability of the harpoons are incorrect, barely doable. However as a druid you can just form to them.
When you finally manage to get on a drake and kill an NPC, you don't get it registered in the quest.
Important that this quest works or is set to auto complete as you need the rep for items.