Hero Stats
CP Combat Power contributes to the total CP of your account. This value for heroes increase on the gear, the skill levels and the level/ascending of the hero.
STR Strength is used for heroes (mainly Commandos) that use WPN DMG in their first skill. Increasing this stat increases base attack and skill attack of these heroes.
INT Intelligence is used for heroes (mainly Riflemen) that use TAC DMG in their first skill. Increasing this stat increases base attack and skill attack of these heroes.
AGI Agility increases the defense value of the Hero, which reduces damage taken.
VIT Vitality increases hitpoints of a Hero, which allows the Hero to live longer.
LUK Luck increases the Initiative of a Hero. The Hero with the highest Initiative attacks first in a battle round. The Hero with the lowest, attacks last.

Gear Stats and Hero Skills
Crit Rate Critical Rate increases the chance of a critical hit of a Hero's basic attack or skill. A base critical hit deals 130% base damage.
Crit Immunity Rate Critical Immunity Rate reduces the chance of a Hero being hit by a critical attack.
Crit DMG Critical Damage increases the damage a critical hit deals. A base critical hit deals 130% damage.
HP Hitpoints of the Hero and soldiers in battle. Increased by HP bonuses and by increasing the Hero's VIT. When the HP reach zero in battle, the Hero dies.
ATK Attack boosts the WPN and TAC stat of a hero which increases damage dealt by a hero.
WPN ATK Weapon Attack increases the auto attack damage and improves the Hero skills for WPN DMG scaling Heroes.
TAC ATK Tactical Attack increases the auto attack damage and improves the Hero skills for TAC DMG scaling Heroes.
DEF Defense decreases damage taken by Hero and soldiers.
WPN DEF Weapon Defense decreases weapon damage taken by Hero and soldiers.
TAC DEF Tactical Defense decreases tactical damage taken by Hero and soldiers.
DMG Bonus Damage Bonus increases damage dealt by attacks and skills.
WPN DMG Bonus Weapon Damage Bonus increases weapon damage dealt by attacks and skills.
TAC DMG Bonus Tactical Damage Bonus increases tactical damage dealt by attacks and skills.
DMG Mitigation Damage Mitigation decreases damage taken by Heroes.
WPN DMG Mitigation Weapon Damage Mitigation decreases weapon damage taken by Heroes.
TAC DMG Mitigation Tactical Damage Mitigation decreases tactical damage taken by Heroes.