Hollow Bones

Sunny pushed his body through the last stretch of the narrow fissure and suddenly found himself in a vast open space. He took a step to the side, clinging to the porous surface of the ancient bone, and allowed Nephis to follow him onto a treacherous ledge. 

She couldn't see because everything was still shrouded in impenetrable darkness, but below them… a whole hidden world was stretching as far as the eye could see, full of vibrant life. 

They were currently inside the breastbone of the dead deity, which was comparable in size to a modest continent. Just like the rest of the bones, it was hollow, encompassing a realm of its own. The bone marrow that had once filled the vast expanse of the sternum's interior was long gone. 

And in its place, a dreadful jungle had grown.