How to beat Finish the Masterwork Weapon side quest.
Guide to Finish the Masterwork Weapon Quest
Finish the Masterwork Weapon is a side quest you can pick up in the underground section of the map inside the blighted village.
Breaking this wall will give you access to the area the quest can be picked up in.
You could collect the large amount of weapons (note that the masterwork weapon will require a sythe, greatsword, or dagger so you could leave one of those there for later).
After picking up the quest from the chest and realizing you need susser bark, the bark can only be found in the underdark and is protected by several level 4 hook horrors which can be devestated to an unprepared team.
The hook horrors can be more easily managed by bringing them up onto this ledge here and after taking a swing you can push them off the ledge for some heavy fall damage, they will then waste their next turn getting back up onto the ledge.
Defeating them you can now loot the tree of it's bark.
Heading back to the forge and using the bark on the fire will turn the flames blue.
Now use either a greatsword, scythe, or dagger on the forge to finish the masterwork weapon.
Enjoy your new Sussur weapon!