Lineage II skills

Lineage II MMORPG is a great game because of it's class system too. You can learn new skills on your main class according to the subclasses you have.

Subclass certifications are needed to learn new skills and can be acquired from one of the Avant-Guarde NPCs on the 2nd floor (Human floor) in Ivory Tower.
How to acquire certifications? At first  you must complete the quest More Than Meets The Eye which can be taken from Hardin at Hardin’s Private Academy.
There are a maximum of 4 skills available per subclass, which means you can have a total of 12 subclass skills once you have all 3 of your subclasses leveled up to 80. The different certifications can be acquired once you have reached these levels on your subclasses:

• 65 level on your subclass – a Emergent skill certificate
• 70 level on your subclass – another Emergent skill certificate
• 75 level on your subclass – you have a choice between a Class-Specific or a Master skill certificate
• 80 level on your subclass – a Divine Transformation certificate