Underworld

The underworld is a place in some stories where bad things happen, and it's usually underground. It's like the opposite of the normal world we live in. In some stories, it's ruled by a scary person like Hades, who is like a king of this underworld.

Usually, when people talk about the underworld, they mean a place where souls go after they die. Some people think that the underworld is a place where souls go to be judged based on their actions in life. If they were good people, they get to go to a nice place called Heaven, and if they were bad people, they go to a scary place called Hell.

Some stories also talk about how ghosts and other scary creatures live in the underworld. These creatures can be really creepy and might not be friendly to people who wander there. In fact, people usually try to avoid going into the underworld altogether because it's dangerous and scary.

So, in summary, the underworld is like a scary place where bad things happen, ghosts and other scary creatures live, and it's where some people think souls go after they die to be judged.