This survival challenge is just the first of 4 challenges in this competition. So there's more to come. That's apart from his suspicion about the purpose of this competition. It is more productive of his time to fight, especially since killing monsters will empower him and boost the processes he is going through than worrying about the things he can't change. The more he kills, the stronger his brand becomes and the smaller his suppression gets.
He looked up and noticed that the birds are still trailing him. They might have decided not to fight him but that's only because they will lose in the forest. They will hound him if he dares to come to the sky. They will be able to attack him from every direction then.
"So no sky for me then." He muttered as he walked in the direction of the mountain.