In Elden Ring's DLC Shadow of the Erdtree, below the massive Legacy Dungeon Shadow Keep lies a flooded district home to deadly creatures and pestering crabs. Accessing the lower section of Shadow Keep requires the player to take a long route, which starts from the Moorth Ruins. Players can come face to face with a powerful boss upon reaching the back side of the Keep. This guide shows a step-by-step walkthrough on how Elden Ring players can reach Commander Gaius in Shadow of the Erdtree.