Originally Posted by
Rex
There are no skill trees like Sagittarian said.
However, when you get to level 10 you unlock the potential to change your class / job to something else. By leveling all the classes, you unlock their abilities, and you can cross class them.
For instance, you're a Marauder currently. Marauders become Warriors. To become a warrior, your marauder has to be level 30 and I believe gladiator has to be 15. Then the quest to become a Warrior can be unlocked.
To become a BETTER Warrior, people will expect you to have certain abilities, like for example, Provoke. Provoke is a Gladiator ability. So you'll find yourself leveling up Gladiator a bit in order to unlock and then "Cross class" the ability Provoke onto your Warrior.
Get it?