Your character can receive experience points (XP)by completing quests and defeating monsters. The XP bar is shown at the bottom of your screen. The bar fills from left to right as your character gains XP. Once the XP bar is full, your character levels up.
In the Goddess of destruction update the following changes have been made:
The character level cap has increased from 85 to 99. The amount of XP necessary for characters of level 20 through 85 to level up has been reduced.
A character of level 84 or lower will not gain XP or SP from killing a monster that is 11 or more levels higher or lower than the character’s level. A character of level 85 or higher will receive an XP/SP penalty when hunting monsters that are three or more levels higher or lower than the character’s level. The penalty increases proportionally to the level difference.