There are a huge variety of skills available in the game. All of them fall into three major types: Active, Passive, and XP.
Active Skills are the most common, and are skills that are only used when you specifically active them. These are most often attack or support skills. Active skills cost MP to use, and require a cool down period after use.
Passive Skills provide a constant benefit, and do not require any action from the player to use. They most often provide general improvements to stats like attack damage or elemental resistance. Passive skills do not consume MP.
XP Skills are special extra-powerful Active skills that are unique to each class. They do not consume MP, but instead require Rage. Rage is accumulated through combat and displayed beneath the player's MP meter. When the Rage meter reaches 1000/1000, it will burst into flames, indicating the XP Skill can be used.
There are several different categories that skills fall under, and they are earned in different ways.
Class Skills are skills unique to each class. Each class has between 18 and 20 class skills, which are learned automatically when the character reaches the required level. The one exception is each class' XP skill, which is learned through the Scenario quests at LV20.
Clan Skills are skills that Clan members can learn. They require the player to be part of a Clan, and the Clan must have a Clan Library built to purchase skills. The higher the level of Library, the more skills are available. Learning or upgrading clan skills requires personal clan contribution points.
Special Skills are other miscellaneous skills learned through a variety of methods, including quests, level progression, and item rewards. These are skills that do not fall under other categories, and includes useful functions such as Town Portal and Soul Seal. It also includes skills for Summon and Mount, allowing you to assign these functions to a handy hotkey.
Using Skills/Shortcut Bar
To use skills, they must be assigned to the Shortcut Bar at the bottom of the screen. The shortcut bar allows you to set up to 30 items for quick access. Active Skills can be added, as can manual-cast Pet Skills, and remedy items. Simply drag the skill or item down to the desired slot in the shortcut bar.
The bottom row of icons is used with the number keys 1-0, while the second row is used with the function keys F1-F10. The third and top row does not have keyboard shortcuts, but is provided to give easy access to items with a click. You can remove items from the shortcut bar by simply dragging them off the bar and releasing.
Class and Clan Skills, as well as certain Special Skill can be upgraded to improve their effectiveness.
Class Skills can be upgraded by speaking with Skill Trainer Mina in Atlantis (228, 236). Each upgrade has a level requirement, as well as a coin and EXP cost. You must be at the required level, and pay the coin and EXP cost to be able to level up a skill. These requirements increase as the skill level increases. Class Skills can be upgraded up to LV10.
Clan Skills can be upgraded by speaking with Aroma at the Library in the Clan Domain. In addition to the level, EXP, and coin requirements, learning or upgrading a Clan skill also requires Clan Contribution, which is earned by participating in Clan events and activities. The availability of Clan Skills is limited by the Library build level. A higher-level Library allows access to higher-level skills.
For either type skill, speak with the associated trainer and open the Upgrade Skills menu. Select the skill you would like to upgrade and, if you meet the requirements, click Upgrade to improve it to the next level.
Certain Special Skills can be upgraded. These require specific items that can be obtained as quest or event rewards.