There are Objects found within the scenes on Knights in the Nightmare; causing enough damage to them will make them yield their items. Damaging objects is how key items are obtained. When objects have taken 100% damage, they become fragile, which will then allow for a Warrior's skill (even with minimum charge) to break the item completely. This is necessary for obtaining more elusive key items, as most objects will respawn after a specific amount of turns. There are some enemies throughout the game that can completely shatter an object, preventing the player from acquiring some key items; it's the player's responsibility to try to prevent this from happening if they care about the item within.
Objects can be broken down into three main categories: obstacle, container, and destructible tiles.
These types of objects are the most common and on average are able to withstand the most abuse from attacks. These objects must be damaged to their fragile state to get the items they contain. Objects like these tend to vary in size, and can easily restrict the movement of certain knights like the Duelist.
These objects generally consist of much more delicate objects such as chests and vases. These objects cannot withstand as much damage as the obstacle ones. Unlike the obstacle kind, container objects can only withstand damage up to 50-99% to be opened up so that their item is revealed. If a container is damaged to its fragile state (100%) before the item is released from within it, the item is lost forever; this forces the player to be mindful of the strength of their unit's skills and charge carefully.
Some chests can turn into Mimics when they are hit. Mimics can attack the Wisp and will slowly try to reach a specific escape tile. The Mimic must be killed before it escapes in order to obtain the item that was inside the chest.
Some map tiles (typically bridges) are considered objects too and can be damaged. These types of objects are generally the most difficult to inflict significant damage on. Duelists and L. Knights can cross over these tiles when they are intact. Like Obstacles, they must be put into the fragile state for them to yield the item they contain. If a warrior smashes a destructible tile, units will no longer be able to cross over them, so be careful before deciding to break them.