In Update 5.3.0, Exiles will have access to a new place for storing loot: the basement. Basements can be built in stone floors starting from level 30.
After you build one, you will be able to go down the stairs to your new storage space, which you can expand for resources.
To expand your basement, you will need a new resource: staples. Staples are available at locations with three, four, and five skulls, in the Traitors' Catacombs, and in the in-game store.
In addition, the basement can be equipped in the same way as your castle. For example, you can improve the floor and walls and place furniture and even some workbenches.