Demon Lord's Cache
From Dungeon Defenders 2 Wiki
Demon Lord's Cache is a secret bonus on Demon's Lair Incursion.
On Demon's Lair Incursion there are 6 secret books that can be activated shattered Across the map. When all are activated a text: A Chest Has Spawned will appear to every player, while chest named Demon Lord's Cache will appear near to where win chests will appear, locked. After Demon die the chest will open automaticly, droping loot. Even Legendary loot