Elden Ring is filled with NPC questlines, some of which are more important than others. While each is interesting in its own ways, a select few, like Brother Corhyn and Goldmask's, are essential if you want to unlock all of the endings Elden Ring has to offer.

Brother Corhyn is one of the many Tarnished NPCs that can be found at Roundtable Hold in the game's opening hours. A priestly figure, he will teach players incantations. To begin his questline, you'll need to have journeyed to the Academy of Raya Lucaria and beat Rennala, Queen of the Full Moon. Return to Roundtable Hold after doing so and talk to Brother Corhyn, who will then remark he will be leaving the hold and setting out on a journey to find the noble Goldmask. Your quest begins here.

Finding Brother Corhyn and Goldmask in Altus Plateau

Brother Corhyn can be found near the map location for Altus Plateau after leaving Roundtable Hold. He will remark he is still looking for Goldmask, who he supposes will be closer to the Erdtree. To find Goldmask and continue the quest, go north to discover a destroyed bridge you'll need to climb atop of. The bridge is located north of the Bower of Bounty Site of Grace. To reach the top, you can either take the nearby Spiritspring to directly jump to Goldmask's location or take a teleporter gate on the southern section of the broken bridge (located southwest of the Minor Erdtree in the area).