Submerged Superstructure

The Submerged Supestructure is a late-game region added by the Downpour expansion.

Overview
Submerged Superstructure is the remains of 's superstrucutre, sunken beneath the 's waves due to the damage her can suffered in its legs after Five Pebbles' first attempt to expel the Rot. While it is best explored by the and plays an important role in their story, most Slugcats can enter the region if they have enough.

It is implied that the explored the Submerged Superstructure themselves, as the Cloak found inside before the 's story has been given to Moon.

If the player comes here as the Saint, they can find an additional Echo inside of Bitter Aerie, commenting on their tenaciousness to get there despite the lack of a reward.