Depths of Vanalf by Brady Hunsaker

Magic is earned by venturing through the depths of Vanalf, a dangerous cave filled with monsters, and depending on how people survive, they emerge with different powers. As an initiate, Hallik is determined to go through Vanalf despite the danger, hoping that the magic will help him locate his lost father, but when monsters start showing up on their island, the entire nation is on high alert. This could only mean one thing. The shield that has been protecting them from the fallen world is failing, and it’s only a matter of time before it breaks completely. Hallik pairs up with three others, hoping they can find a way to restore the shield, but their path must first take them through the depths of Vanalf.