You can learn new skills on your main class according to the subclasses you have.
Subclass certifications which are needed to learn these skills can be acquired from one of the Avant-Guarde NPCs on the 2nd floor (Human floor) in Ivory Tower.
In order to be able to acquire certifications you must first 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
Removing and resetting subclass skills
Deleting a subclass to reroll a new one will not erase the subclass skills you've already learned, but you won't be able to learn additional skills from your new subclass for the levels you've already acquired certificates. E.g., you have learned two Emergent skills from the 65 and 70 levels of your subclass respectively, then you reroll a new subclass, but you can't acquire certificates for level 65 and 70 of the new subclass unless you erase your previous subskills.
You can only remove all subskills from all subclasses on your main class. This is done by paying 10 million adena to Avant-Guarde NPC. You cannot chose which subskills to remove.
Certificates in your inventory that you haven't used up yet are also deleted when you pay 10 million adena to erase your subclass skills.
Subclasses are categorized broadly as Warrior, Rogue, Knight, Summoner, Wizard, Healer and Enchanter. The Class-Specific and Divine Transformation subclass skills available to you through certification depend on the categories of your subclasses, as follows:
What follwos is a complete list of available skills, with exact effects and bonuses (some not confirmed).
Emergent Ability skills
These skills are avaialable regardless of the category your subclass falls to.
+18 Heavy/+13 Light/+9 Robe P.Def
These skills can be stacked up, with maximum of level 6 if you chose to learn the same skill from both 65 and 70 certificates for each of your 3 subclasses. E.g., you get 6 Emergent Ability certificates from all your subs and use all of them to learn the Physical Defense skill. In the end you get Lv6 of the Physical Defense skill.
Master Ability skills
These skills are avaialable regardless of the category your subclass falls to.
Great Physical Defence
Greatly increase P.Def
+59 Heavy/+44 Light/+29 Robe P.Def
Great Magic Defence
Greatly increase M.Def
Great Physical Offense
Greatly increase P.Atk
Great Magic Offense
Greatly increase M.Atk
Increase critical rate
Unlike Emergent Ability skills, only Defense and Magic Defense of the Master skills can be learned/stacked up above Lv1 (up to Lv3).
Class-Specific Ability skills
Keep in mind that Class-specific skills can't be stacked up, e.g. you can't learn Boost CP or any other skill twice.
Increases the maximum range of bow and crossbow attacks
+100 distance increase
1% chance to increase Crit.Rate when attacking
+30% Crit.Rate for 15 seconds
Knight Class (Paladin, Dark Avenger, Temple Knight, Shillien Knight)
Increase Max. HP.
Reduce the amount of received critical damage
5% crit.dmg decrease
3% chance to increase P.Def and M.Def when under attack
+20% P.Def and M.Def for 15 seconds
Summoner Class (Warlock, Elemental Summoner, Phantom Summoner)
Increase Max. HP and Max. MP
+147 HP and +74 MP (+3-4% ?)
Resist Element Attribute
Increase Fire, Water, Wind and Earth Attributes resistance
+5 to Elemental Attributes
3% chance to increase M.Atk, Cast.Spd, P.atk and Atk.Spd when under attack
Increase M.Atk, P.atk by 7% and Cast.Spd, Atk.Spd by 8% for 15 seconds
Wizard Class (Sorcerer, Spellsinger, Spellhowler, Necromancer)
Increase resistance to magic attacks
+5% chance for attacking magic to fail
Increase the amount of MP gained from recharge
+20 MP per recharge
Counter Mana Steal
3% chance to steal MP from the opponent and recover it as your own when under attack
Healer Class (Shillien Elder, Elven Elder, Bishop)
Increases effectiveness of received healing
+19 HP per heal
Resist Divine Attribute
Increase Holy and Dark Attributes resistance
+5 to Divine Attributes
3% chance to restore HP when under attack
Enchanter Class (Prophet, Warcryer, Inspector, Swordsinger, Bladedancer)
Increase Max. MP
+148 MP (+5-6% ?)
Increase MP regeneration rate
3% chance to become temporarily invincible to damage (but not debuffs) when under attack
Celestial Shield type of buff for 5 seconds
Divine Transformation Ability skills
You receive a seal book of transformation instead of certificate for these skills. You can learn them via the transformation menu on the Avan-Guard NPC
Divine Transformations, although more sophisticated, follow the rules for regular transformations. This means you cannot use your regular class skills, your subclass skills remain active, your stats are determined by your equipment and the class type of the Divine Transformation in use.
Reuse time, Sacrifice Skill and Transformation level
Each Divine Transformation lasts 30 minutes and has a cooldown/reuse time of 3 hours.
Each Divine Transformation has its specific Sacrifice Skill. All sacrifice skills bring your HP and MP down to zero for a certain amount of time during which you can't be healed through skills or potions. The Sacrifice Skill usage conditions depend on the type of your subclass: Fighter-type subclasses - 30% or lower HP; Mystic-type subclasses - 10% or lower MP.
Each transformation can be learned up to level 3 if you happen to have more than one subclass of the same type. E.g., if you have 2 Warrior-type subclasses and they've reached level 80, you can learn Warrior Divine Transformation level 2. If you have 3, the transformation learned would be level 3.
Divine Transformations and their respective skills
What follows is a list of all Divine Transformations, along with their specific skills.
Attacking enemy using hurricane force, can critical, power 2904
Attacking enemy at range using sword force, can critical, power 2323
Attack surrounding enemies (earthquake), ignores shield defense, can critical, power 2323
For a short duration greatly increase your own attack strength, effect 2
Poison an enemy with a poison needle, power 1689, effect 3
Sacrifice your own life to increase party's attack power
Hate, power 6752
Hate Aura, power 6752
Attack target while rushing at target, stuns target, can overhit, power 1162
Attack surrounding enemies, stuns enemies, ignores shield deffense, can overhit, power 775
Greatly increase your pdef, mdef and resistance to buff cancelling attacks, cannot move while in effect, effect 2
Swing your axe to hit enemies in front of you, power 2322
Rush attack, power 1900
Sacrifice your life, boosts party's defenses (pdef and mdef probably)
Divine rouge is a combination of archer and dagger, hence you get skills for both weapons, but the skills are also limited by weapon-type...
When attacking enemy has chance of removing buffs (not sure..) and stunning target, can only be used with a bow, can overhit, power 2323
Shoot two arrows simultaneously, lethal strike is possible, can overhit, power 6195
bleed shot, can over hit, power 1549, effect 3
strong attack, can instant kill, can only be used with dagger equipped, power 6969
for a short duration increase your evasion
Attack enemies behind you, power 2111
Sacrifice your life, increases party's evasion
Heal target's HP overtime, power 946
Instantly recover target's HP, power 826
Heals party's HP and increase HP regeneration, power 400, effect 5
Resurrection, recovers 70% of target's experience lost
Removes debuffs from target
Sacrifice your life, recovers HP and MP of all party members (not yours obviously)
Aura Flare, during PVP your matk will decrease, power 102
Sacred magic attack, can overhit, power 128
AoE sacred attack, power 64
AoE sleep, while slept target's resistance to sleep increases (doesn't say it won't land at all)
Increase dark resistance, decrease holy resistance, effect 3
Sacrifice your life, gives M.Atk to party members
PoWater, consumes 5 spiritore
PoFire, consumes 5 spiritore
PoWind, consumes 5 spiritore
Target CoV (not party buff), consumes 5 spiritore
AoE Root, if target rooted already it has no effect
Sacrifice your left, increases all abilities of party
Summon sacred beast, summoning consumes 2 A Crystals, consumes 1 extra A crystal each time it usually consumes crystals
Transfer pain, continuously consumes MP
Final Servitor (CoV for summon), consumes 20 spirit ore
Servitor Heal, power 991
Sacrifice your life, increases party's critical rate