Its caverns link the Underworld to the Feymarch, land of Eidolons. The cave is littered with many lava-filled pits, which will damage the entire party if stepped on. Rosa can prevent this damage by casting Float on the entire party. The spell will need to be recast whenever a new floor is reached. On the third basement level of the Passage, a blue prism awaits that will teleport the party to the Feymarch. In The After Years, it is part of the storyline and is thus required to be visited.