The Ultimate Lair is a dungeon located in the Dead Dunes inhabited exclusively by Last Ones, with one guarding each floor, save for the final five floors, four of which have only healing items, and the last floor containing a superboss. Killing the Last Ones here exterminates the respective enemy in all of Nova Chrysalia, making some selective extinction in the Ultimate Lair useful for farming items from monsters that have a low spawn rate. Killing Last Ones earns achievements and trophies.