Pillars of Eternity II: Deadfire

To start this quest, you are going to want to travel to Junvik village. Talk to Tatok and agree to find his son. Leave the village to the north to find the Drowned Barrows. Once there go straight and you will eventually find worshipers and Tatok's son. You have two options here: fight Nemnok or agree to help him find the grimoire (which you do not need to complete to get this achievement). In order to avoid the fight, you need a diplomacy skill of 8. If you want to fight him, he will have up to 10 minions to help him. Make sure you are at least level 18 if you decide to fight him. Regardless of choice, go back to the village and turn in the quest.