Dual class simply means that you can pick and play two completely different classes and be able to fill their roles. For example, you can play either as a Knight and tank for groups on elite quests and dungeons, switch over to a secondary class to heal or dps or you can even create your own hybrid to fill more than one role at the same time.
Once a player reaches level 10 they can learn their secondary class. The player has the option to choose any two of the 6 available classes for their secondary class. It is as easy as talking to an NPC and switching between the two or playing as a hybrid.
Inside of Runes of Magic player will find themselves able to initially pick one of six classes upon character creation. The class you initially start with doesn't neccessarily mean that is the class you will end up with. While choosing to Dual Class, picking your initialy primary class isn't all that important. However, it is important for you to know just a little bit about each class before you begin your adventures.
Warrior
Unlike most MMORPGs the warrior class in Runes of Magic is not meant to be a main tank. Rather, the powers of a warrior are meant more for outright melee raw damage. However, in the later levels a warrior tank is possible but knights are more suitable as main tanks. Aside from raw melee damage, the warrior has several area of effect abilities that allow him to strike at several targets at once which makes this class a juggernaut that can dish out some insane melee damage.
Scout
The ranged DPS for Runes of Magic is the Scout. They pride themselves on striking down their foes from range with a bow or crossbow. While most of their abilities are used for damage, there are a few tools at their disposal that helps them detect stealthy players and prevent their targets from reaching them.
Rogue
A typical melee stealth DPS for Runes of Magic. The rogue relies on sneak attacks, poison and attacks from behind to devastate unsuspecting victims. Aside from the ability to stealth, one of the most unique abilities a rogue posses is to increase the chances of better than average loot dropping from slain creatures.
Mage
The Mage class is the typical caster DPS in Runes of Magic. They control the forces of elements and bend them to their will to take out their opponents. They are quite possibly the best damage dealers in the game excelling in both single and multiple target destruction. Aside from a huge amount of personal damage they can inflict, they also posses a few spells that can protect their allies.
Priest
The main healing class in Runes of Magic is the Priest. This is also the only class that has the ability to heal and revive fallen comrades. They use the element of water to heal and protect their allies. However, don't let that fool you for the power of water can also be sued to dish out an impressive amount of damage as well.
Knight
The true tanking class in Runes of Magic is the Knight. The Knight class posses the best tools for both damage mitigation and aggro domination. While their damage is relatively low compared to other classes, they excel in the ability to solo many things other classes cannot. If tanking is your thing and the idea of soloing some of the most powerful creatures in the game excites you, this class could be for you.