Solasta: Crown of the Magister

Simliar to the Champion of the Principality achievement this will unlock just following the main storyline and doing whatever side quests come up. It unlocked for me after recovering the Necromantic stone from Mardracht. then clearing all the mobs on the outside of the castle. Then entering through one of the entrances that I hadn't used before. You can enter through the graveyard, or through two wells. Each entrance you use will increase your reputation.