STR (Strength)

Every 5 STR adds 1 Melee Damage.

Every 5 STR adds 1 Physical Critical Additional Damage.

DEX (Dexterity)

Every 1 DEX adds 0.2 Accuracy.

Every 1 DEX adds 0.2 Evasion.

Every 1 DEX adds 0.00725% ~ 0.01125% Critical Chance depending on class.

Every 5 DEX adds 1 Long Range Physical Attack Power.

INT (Intelligence)

Every 5 INT adds 1 Spell Critical Additional Damage.

Please note that your damage will not show decimals and will be rounded.

Every INT adds to the base resistance (to all elements), which is equal to round( sqrt(INT) + 0.0495 , 2) (round to two decimal places the sum of the square root of INT and 0.0495).

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 0.5 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.

Obs: However, buffs on HP Recovery, MP Recovery, Attack Speed, Moving Speed, Vision wil not be stacked. When those buffs are performed, the higher level buff will override the lower.

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 25% of their MP Regen. (S1 was 1/3, now in S2 its 1/4)

HP does not regenerate naturally during combat.Source

Defense

In S2, the damage reduced is % based on an amount of defense, wich is calculated using this formula:

y=22.994*ln(x)-101.19

In wich:

y = % of damage reduced

x = defense

Also, it seems like defense caps at around 80% reduction, wich is roundly 2700 defense, although this is not confirmed.

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. NOTE: Accuracy does also help with long range physical damage, not only short range physical Damage!

Evasion

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

Provided attacker accuracy is same as your evasion, you have around 5-10% chance to dodge. I believe 5% is minimum, since i dodged mobs 50lv higher than me. If attacker has 1000 accuracy, then every 1000 evasion you have above attacker accuracy should give you 10% higher chance to dodge. So if you had 10000 evasion, you would have 100% chance to evade. It's not very useful in PVP, since players can easily get to high accuracy. for example, a lv 30 rogue with lv 10 accuracy buff/DNA would have around 2-3k accuracy, so you would need 20-30k evasion. which is something you could expect from maybe lv 65+ SR. or SH that spent lots of work with xeons. Same with a Inferno-Druid.

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.