Solution

As soon as they got back to the palace, the Elves immediately took Anna underground. The path leading underground was dim and lit only by a few torches lining the walls.

The air below was also humid and feels worse than above.

Erend, Billy, and Lt. Boartusk who had entered the palace underground for the first time felt a strange sensation as soon as they were there.

The Elves took Anna and put her in a cell. The bars of this cell is made of what appears to be wood. Not of iron like they used to see in their world.

But before any of the three of them asked if these bars were strong enough to hold a person, they saw several prisoners huddled in the cells.

They saw a creature with pale green skin whose body was so large it almost resembled a giant, a brown-skinned creature with horns on its head, and also an animal that was probably a bear.