RO currently has 10 classes and the ability to Multi-Class. Each class was inspired by either Diku/Silly, D & D, or J.R.R. Tolkien (and I suspect the first 2 were themselves inspired by Tolkien). Here you will see a fairly decent description of each Class. Including level of difficulty to play. It should be noted that the level of difficulty is just the opinion of this writer. Some people's thought processes may make certain Classes a lot easier for them. However, when the Classes were re-defined for RO5, it was under the assumption of the difficulty rating defined on each Class specific page.