A rogue is a damage-dealing machine. Their single most important focus is taking enemies down quickly. Well-equipped rogues are capable of equaling even mage damage output when grouped with a decent tank.
A rogue’s special attacks are fueled by energy, a constantly-replenishing gauge located below their hitpoints. Each attack deals bonus damage and garners the rogue a combo point. These combo points can then be used to perform finishing moves that deal a large amount of instant or DoT (damage over time) damage. Unlike mana, the energy bar refills very quickly, leading to very little downtime.
Stealth is another key weapon in a rogue’s arsenal. Many quests that ask the player to kill a certain mob or open a certain chest can be completed more quickly by simply stealthing past most of the mobs to the objective, then stealthing out again. Stealth is also a huge advantage in PvP.
Lockpicking is a skill unique to the rogue class. It can be used to open locked treasure chests and even open some doors within instances that normally require keys. Opening lockboxes is also a decent way to generate income, as most players are willing to tip a rogue who cracks one open for them.
Rogues can also learn to apply poisons to their weapons which can slow the enemy or deal damage over time.