Get Obsidian Elf Sniper's Bow

Journal
''I met a Highvale Outskirts guard who required that I prove my mettle before sending me to see his captain. He asked that I find an Obsidian elf sniper and put an end to his attacks upon incoming refugees. To prove that the deed is done,I'm to bring back the defeated elf's bow. I should look nearby for this sniper, probably near outcroppings of trees and rocks.''