Hmm… are you wondering, can you add to the classes string files? If that is the question then no, you can only change class/skill names in the string files.
Now, in terms of making new skills, with new effects, you can code effects and add them to the games .effects file.
Classes that have done this include – Assassin, and Courtesan – a bunch more by Actionjack.
If you don’t want to get into adding/altering effects, you can do what I do and use vanilla skills from different classes to form a unique class. You can still alter attributes and numbers within the vanilla skills and re-name them. For examples of this you can see my classes, Paladin, Blackguard, Apothecary, Maiden, etc.
If you are serious about making classes, then you will need to look back at older threads, there have been many posts about what you need to do and suggestions on how to do it. Have a look at the files in current custom classes to compare what you need to do.
Current class mods/variants:
Shadow-Dancer, Maiden, Knight, Dame, Evoker, Warlock, Apothecary, Psionic, Treasure Hunter, Gladiator, Blackguard, Valkyrie, Shadow Valkyrie, Vampiress, Lycan, Court Magus, Songstress.
DOWNLOAD FROM: http://www.nexusmods.com/darkestdungeon/?
My personal Art work and Novels: www.stevenmouland.com