In the higher grounds, where the forest took over… That's the location where Artemis decided to teach Mark how to hunt. How to hunt people, instead of how to hunt wildlife.
Of course, it was all just practice, which means that there were no practical tests subjects for Mark to practice on. Mark had to get the basics first, such as certain exercises that will help him with his mobility and strength, and hand to hand combat. Only after such basics can Mark move on to the next stage. A stage that doesn't involve killing yet, as well…
