Levels
From ROSEna Wiki
Every player has a level associated to their character. When a player starts off as a Visitor, his initial level is 1.
As the player completes quests and kills monsters, he receives EXP. After obtaining a sufficient amount of EXP, he levels up. The amount of EXP required to level increases somehow exponentially as the player gains in levels: basically, low-level players don't need a lot of EXP to level while high-level players need a huge amount of EXP. Fortunately, monsters around the player's level tend to give fair amounts of EXP (which doesn't make going to the next level an impossible task).
