Player Stats

HP
HP: Player's Hit Points

MP
MP: Player's Mana Points

Primary Stats

STR
Strength: Every 1 STR adds 0.2 Melee Damage and 0.2 Critical Additional Damage

DEX
Dexterity: Every 1 DEX adds 0.2 Accuracy, 0.2 Evasion. Every 1 DEX adds 0.00725% ~ 0.01125% Critical Chance depending on class. Every 5 DEX adds 1 Range Damage (Crossbow/Launchers).

INT
Intelligence: Every 1 INT adds 0.3 Spell Damage. Every 5 INT adds 1 Spell Critical Additional Damage.

CON
Health: Every 1 CON adds 5 HP. Every 5 CON adds 1 to HP Recovery

MND
Spirit: Every 1 MND adds 4 MP. Every 1 MND adds 0.3 HP Restoration to direct heal spells. Every 5 MND adds 1 to MP Recovery. Adds 0.011% ~ 0,0138% Skill Critical Chance reflected by class.

Substats

HP & MP Recovery
HP and MP Recovery occurs once every 3 seconds. The amount regenerated depends on the state of the character, as well as equipment, and stats.

* Sitting
  A sitting or resting character gains 100% of their HP and MP Regen.
* Standing
  A standing character gains 50% of their HP and MP Regen
* Combat
  A character in combat gains 30% of their MP Regen.
  HP does not regenerate naturaly during combat.Source

Defense
Every 10 Defense reduces Melee Damage by 1 point.
Block Chance & Block Defense
Block Chance is the percent chance that a melee attack will be blocked. On a successful block, Block Defense is the amount of damage that that melee attack is reduced by.

Accuracy
Player's chance to successfully hit the target with a physical attack.

Evasion
Raises your ability to dodge all types of attacks.(asside from attacks that cannot miss)

* with what chance? it is most likely their accuracy divided by your eva. ex, someone with 3000 acc/ 15000 evasion, about 20% chance of hitting.
* Another stab at accuracy formula. (Enemy EVA - Your ACC) / Your Level.

Critical Chance & Critical Additional Damage

Critical Chance is the player's chance to perform a critical hit with any auto attack. On a successful Critical Hit, damage = base x 2 + Critical Additional Damage.
Skill Critical Chance & Skill Critical Additional Damage
Skill Critical Chance is the player's chance to perform a critical hit with any skill that heals or damages HP. On a successful Skill Critical hit, damage/heal = base x 2 + Skill Critical Additional Damage. Status effects are not affected.