The Key is an item that went unused in Hello Charlotte Episode 1, but has since gone on to appear in Hello Charlotte: Delirium and Hello Charlotte Episode 3.
Hello Charlotte 1[]
The Key is found in the database of Episode 1, but lacks a description and does not appear to do anything of significance. It also shares its sprite with the Silver Key and the Unknown Key, the former being an item necessary for progress and the latter also unused.
Hello Charlotte 3[]
The Key reappears in Episode 3 on the ninth floor, during the first puzzle in the Eden challenge. To acquire it, first obtain a Soda Can, then use it in front of the fridge in the kitchen after the power has been restored to the apartment. The soda will explode and reveal the key inside it. This key can then be used to open up a drawer on the laptop's desk to acquire the USB Stick that's inside.
Delirium[]
In Delirium, there are two "Key" items with the same name. They are stored in the "keys" category of the inventory.
The First Key[]
The first key is found in The REDRUM in the basement. It's inside the cabinet furthest away from the room's entrance, and is needed to unlock the poisonous room.
The Second Key[]
The second key is found in the Meat World. After inspecting the machine, head to the western room and inspect the hole in the back wall, then choose to put your hand inside in order to obtain it. This key simply activates the machine in the eastern room.