Experience
"Experience" is accumulated from defeating monsters and completing quests. The amount of experience you currently have collected is shown in an orange bar on the top of your screen, and in the "EXP" bar of your status window.
If your experience bar fills all the way up, your level increases by one, and your experience bar starts from zero again. Experience you have gained stays - you will not lose experience for getting knocked out (however you also cannot gain any experience while knocked out either).
Experience Cap
The maximum amount of experience you can get from killing a monster is 20% of a level. Therefore, even if you killed a level 10 monster while level 1, or completed a quest that rewards a lot of experience points, you will not gain more than 20% of a level.
Experience in a Group
If you are in a group with other players, experience that you obtained is split up between all group members on the same map. Characters that are higher level get a greater share of experience points, so everyone levels roughly at the same pace. For this reason, it is a good idea to fight with other adventurers that are roughly the same level as you.
You can enable level synchronization in the group settings, which gives everyone in the group the same level. In this case, experience is shared equally.
Characters that are at the level cap will still receive their share of experience, even though it essentially has no effect.
Pet Experience
If you have your pet summoned and fight, your pet will automatically gain experience as well. This includes experience from killing monsters, and MVPs, but not quest experience.
The experience awarded to your pet is bonus experience - your pet does not take it from you or anyone else. Your pet does have its own experience cap, and its own threshold level below which a monster wouldn't give experience (so monsters that are "Low Level" to your pet wouldn't give experience, whereas a monster might be "Low Level" to you, but not to your pet).
Notes
- Any group member that is involved in the fight with a monster increases the amount of experience that monster gives when killed by 25%.
- For World Bosses, any player involved in the fight will increase the amount of experience the MVP gets by 25%.
- If a monster is much lower or much higher level than you, the amount of experience you get is greatly reduced.
- You need to be at least eligible for experience in order for your pet to get experience as well. Therefore, if your pet kills a monster entirely by itself, you wouldn't get experience, and neither would your pet. You need to land at least one hit, so your pet learns!