If you haven’t read my article about Adventurer Handbook and you don’t have any idea what is it then you may check it here.

Here are the list of Adventurer’s Class and their skill Benefits.
Note: You need to learn the skill first by purchasing the skill in Prontera, You need to be in the exact Class before you can purchase the skill. 
Go to the North of Protera and Talk to Mayfair Linse.

Appretince
Adventure Level Required: Level NONE


Scout
Adventure Level Required: Level 5


Adventurer Class F
Adventure Level Required: Level 10


Adventurer Class E
Adventure Level Required: Level 15


Adventurer Class D
Adventure Level Required: Level 20



Adventurer Class C
Adventure Level Required: Level (NO IDEA as of the moment, If you know, Please leave a comment)


Adventurer Class B
Adventure Level Required: Level (NO IDEA as of the moment, If you know, Please leave a comment)