An experience point (abbreviated EXP or XP) is a unit of measurement for character level advancement. Advancing to the next level requires a fixed amount of experience points.
In Dragonica, you generally only get XP from killing mobs and completing quests, alternatively leveling together with your friends in your buddy's list together in the same map will also yield Friend Point which can be traded in towns for Exp (So always remember to Buddy your party members to make full use of this system). When your HP reaches 0, you will lose 3% of your EXP.
This is based on the concept that as characters defeat stronger enemies, they gain combat experience that allows them to improve their skills. 20 combo for 1.1 EXP, 40 combo for 1.2 EXP, 60 combo for 1.3 EXP, 80 combo for 1.4 EXP and 100 combo for 1.5 EXP. This system is descended from D&D and is present in some form or another in almost all roleplaying games.