Infinite Upgrade Player System

I don't know when, something called a "door" appeared in the world I live in, which connects to other dimensions. You don't know what you will face. From the moment you step into 'it', everything will become unknown! What you are facing may be a 'god' or a 'demon', demon hunters! Pick up your courage! Pick up the sword in your hands! For your home, for your loved ones! No matter what it is! Beat it!