Stats

Health Points

Your total health points. They go up with the Vitality Stat.

Damage

Your base weapon damage. Some skills benefit from it. It can go up with stats or weapon damage.

Vitality

Vitalty is the stat that increments the total health points by an ammount:

Vitality
HP: Starting HP + 25 * Vitalty Points

Power

Power is the main damage stat. Power increments the damage for some skills.

Power
Increment depends on skill

Speed

Speed decreases cooldown for skills. Also the more speed, the faster you will attack. In order to calculate it:

Cooldown Reduction
Cooldown Reduction: 0.87 * Speed Points / ( Speed Points + 80 )

Attack Speed
Attack Speed: Initial Attk Spd - Initial Attk Spd * Cooldown Reduction