Cage is a piece of scenery found atop The Grand Tree, in platforms in Underground Pass and in the grill tile room of Underground Pass.
There are a total of two cages and Charlie is in the other one. The player is put in the other cage by Glough during The Grand Tree quest and later freed by King Narnode Shareen.
Cages have an open option but it has no effect.
The first cage in the Pass is opened by crossing the 5x5 grill tiles and the pressing a lever.
There are also cages with Souless in them atop stone platforms, held by some bridge supports in the deeper dungeon. Klank's Gauntlets are required to safely search the cages in order to find Iban's conscience.