Every character's progress is represented by his level. New characters start at Level 1, and steadily achieve higher and higher levels (currently up to Level 51 in english versions).
To increase his level, a character must gain enough experience points. The required amount of experience becomes higher as the character is leveling. Experience is gained by killing enemies and by completing quests. Players get less experience from killing monsters if the level of the enemy is lower.
Every level you gain will reward you with one talent and one stat point. Once you reach Level 10, you will be able to purchase Rubies from your class trainer to unlock new talents. Additionally, for every 5th level after Level 10 you will receive two talent points instead of one (including at level 10). You will have a total of 53 talent points at Level 47 though you can buy Special items that icrease the amount of Talent Points you recieve.