The Family Blade - Skellige
Location: Kaer Trolde Harbor
Quest Giver: Kaer Trolde Notice Board
Other Requirements: N/A
This quest is started by accepting the notice from the Kaer Trolde Harbor Notice Board or by stumbling onto the pack of bandits that are pictured above and looting the quest items from them. Assuming that you got this quest from the Notice Board, the first location you'll have to visit for this quest is the area southwest of the Miners' Camp Signpost.
Here you will find a group of bandits (pictured above) that you'll need to defeat. Loot the Thief's Journal from them and read it to learn the next location you need to go.
It's an area far to the south of where you are now, down here there will be more renegades/bandits to kill and they'll drop another Thief's Journal for you. Our next location is far to the northeast of where we are now - lots of traveling for this quest!
All of the locations you have to visit are marked on my map above, as well as every hidden location revealed. Click to enlarge it if you're having trouble viewing it. The last location that we'll be visiting is the area to the northeast called Whale Graveyard. There will be more thieves here for you to dispatch and loot for the final quest items.
Now you can return to Olaf in Kaer Trolde to complete the quest.