Summary[]
Denizen Cave in Tren is accessible after you have passed through Blue Creek, however you cannot pass through the cave until after receiving the Denizen Pass key item. The pass is received after clearing the events at Valley of Carnon.
Path through the Thorns Maze[]
The red #2 tiles have thorns and will deactivate the Denizen Pass.
The blue tiles are a valid path.
The blue chest on the left contains the very useful portable Crafting Bench and the chest on the right contains a less useful Orange.