A person can have a total of 10 tiers/ranks. Your starting class is tier 1. At the level cap for your specific class you will have a leveling quest that will require you to finish it to increase your tier and evolve into a stronger class. Each tier has a different max level and different XP requirements to increase it. For tier one it starts at 100 XP to increase from level one to two and doubles for each level after. The level cap goes from ten for level 1 to double that at tier two. This doubles again for tier three but resets for tier four. This happens every three levels but level ten is unique as discussed later in the novel.