The library is in the west area, and bad luck can also pass through the north.

But now I don't need a key.

Just go directly to the copy door in the west (the door is in the west of the Doomsday Hammer Arena, and there is a wooden door outside, but it can be opened directly).

Remember that the door of the North District Library is at 9 o'clock in front of the sinking square after entering the book, and it is also a wooden door that can be opened directly.