The Pirran Caverns are a giant underground cave system, running the entire length of Deltora. The Caverns consists of three isles were the three different groups of Pirrans settled down, after they were forced out of Pirra by the Shadow Lord. The Cavern are filled with water, forming an underground ocean, with the ceiling changing colour to accmodate with the gemstone of the tribe it is situated beneath.
Each Isle's people had a piece of the Pirran pipe which was split due to trickery by the Shadow Lord. The Plumes had the mouthpiece of the flute, although it was stolen and eventually ended up with Glock. The Auron's had the Middle Stem, and the Keras had the Endpiece.