Preview to upcoming events(Unconfirmed)

I'm assuming you mean Mastery Books and not skills books.
But all of the skills require mastery books, except for Maple Warrior and Hero's Will.

thats a big ol' fat nope.

 Spoiler

Fourth Job :

Sanrenzan - Rai [Master Level : 30]
[Required Skill : Sanrenzan - Jin Level 20]
Description : An upgraded version of previous Sanrenzan attacks. Press the skill key continuously to attack up to three times, dealing 220% twice, 250% twice, and 300% three times to up to 6 targets. In addition, at a 30% success rate, you will deal 410% damage with an extra hit to 6 targets. The extra attack numbers will show up as green numbers.
This skill does not require a Mastery Book.

Shinsoku Musou [Master Level : 30]
Description : Attacks a single target 10 times for 162% damage per hit.

Yousousen [Master Level : 20]
[Required Skill : Senpuuzan Level 20]
Description : Jump up into the air and quickly charge downward at enemies to do 190% damage to 8 targets 6 times. This attack can be combined with many other skills in your arsenal to greatly reduce delays and perform very fast and powerful attacks. In addition, Shouryuusen, Dankuusen, and Senpuuzan skill damages are increased by +100%.

Issen [Master Level : 30]
Description : Rush at your opponents with amazing speed and power. Hit up to 15 targets for 455% damage each hit. When used, receive a 40 second buff that increases your critical rate by 45%.
[Cool Down Time] : 90 seconds

Gouken [Master Level : 20]
Description : For 180 seconds, increase status effect resistance and elemental resistance by 30%.

Jinsoku [Master Level : 30]
Description : At a 45% success rate, when you successfully dodge an enemy's attacks, you will receive a buff that will reduce the damage you take by 35%. In addition, your dodge rate will be increased by 40% passively.

Ittou Ryoudan [Master Level : 30]
Description : A passive buff that increases your ignore target defense stat by 35% and your total damage by 30%.

Akatsuki no Yuusha [Master Level : 30]
Description : Increases all stats by 15% for 900 seconds.
This skill does not require a Mastery Book.

Akatsuki no Sakura [Master Level : 5]
Description : Eliminate the seduce status effect.
[Cool Down Time] : 360 seconds
This skill does not require a Mastery Book.

Saki no Saki [Master Level : 15]
Description : When attacked, at a 20% success rate, your character will counter the enemy's attack, hitting up to 3 targets for 195% damage.
This skill does not require a Mastery Book.

Guren Jabaku [Master Level : 10]
[Required Skill : Kurenai Jabaku Level 10]
Description : An upgraded version of Kurenai Jabaku; increases the activation rate to 30% and increases the damage over time to 170% per second for 5 seconds.
This skill does not require a Mastery Book.