Your damage is split into two categories: Physical and magical.

For the most part, magical damage is by using x, for the exception of elsword which X is just a stronger swing.

All z attacks are physical.

Skill Damage

Dame of skill is dependent on their percentages.

For example, if your attack power is 5,000, and the percentage is 1,000%, you'd do 50,000 damage.

Percentages vary, a really huge number like 1000% means that it's a one shot move, or at least a very limited number of hits.

Small percentages means several hits.

Such as windmill's percentage is only at 93%, however it does 43 hits in awakening mode.