Experience is gained through completing Dungeons, PvP or by completing certain missions and is required in order to gain levels. Some items will increase experience gained, such as Queen's Jewel, QuQu Helmets, New Continent Gem, Slime Helmets, and Turtle Shells. Sometimes, there are events that will increase experience gained from dungeons and PvP, either for one character, or for all of them.
The current level cap is 85.