A creature inside the cage cannot go away it by nonmagical implies. When the creature tries to use teleportation or interplanar travel to leave the cage, it should initial come up with a Charisma conserving toss. At https://siobhanirgi602916.bligblogging.com/30801922/the-smart-trick-of-dnd-5e-far-traveler-that-nobody-is-discussing