This is another Qeynos Bounty quest, designed to raise faction for Qeynos Citizenship.
Talk to Gil McMartin in the Commonlands. He sends you to Nektulos Forest to kill Lin'Val Zar'trax. He spawns near -1435,42,-1395 as a single up arrow mob that scales to the level of the quest holder.
Once Lin'Val is dead, return to Gil McMartin in the Commonlands to collect your bounty.