It's been a month since they left the fortress. In the beginning, the terrain hadn't changed much and the monsters they encountered weren't very strong, so the skeletons were hopeful that they wouldn't face too many problems at the beginning of their journey.
They couldn't be more wrong.
After marching for almost a week without stopping, the terrain began to change from dry grass hills to tall grass savannahs. But the biggest change has been in the world's energy density.
Most skeletons didn't notice the change right away, but more sensitive ones like Athos and Treevor noticed the difference. Treevor didn't mind as he was used to it, but Athos was shocked.
With the world's energy so dense, it would be much easier to develop the core by training in the desert. This also means that the monsters would be much more powerful than those outside, but Athos only realized their real danger after the first wave of monsters attacked them.