Description
If you learn to strike the weak points on your enemy, it's not so difficult to deliver only a few blows to end a powerful enemy that looks down his nose at you. Although, ordinary people attribute such strikes to coincidence, calling it a lucky shot, critical hits don't happen accidentally, no matter how lucky you are. This skill is impossible without careful observations of your enemy and identifying his weakness. The more you train yourself in this skill, the more opportunities you will have in delivering a critical hit.

Details
The Critical Hit skill adds to damage dealt when the player successfully lands a critical blow. In addition, the Will added from advancing the skill will add to the player's chance to land a Critical Hit.
Every +10 Will adds 1% to critical chance.
Every +5 Luck adds 1% to critical chance.
A High Ranked Counterattack also adds to critical chance.
Critical chance is effectively capped at a maximum of 30%. If your chances of landing a critical hit are above 30% as indicated by the formula below, it is reduced to 30%.
To find out what your chance of landing a critical hit on a monster is, the formula is as follows:
(Your critical %) - (Monster's protection x 2)
For example, you want to try to Critical a Siren. However, she has a protection rate of 30%. That means you need at least a 61% of critical to at least have a 1% Chance of scoring a critical hit. If you have 90% Critical, then you will have a maximum chance of scoring a critical on her.
Players conducted a trial in which a person with 90% critical attacked a black-tailed mongoose (which has 16 protection). Using the above formula, the chance for critical should have been 58%. However, out of 3308 attacks, only 989 criticals were observed; a cap of ~30%.
The skills Windmill, Stomp, Fireball, Ice Spear, and Thunder all ignore the monster's protection when calculating critical chance. However, maximum critical will still be capped at 30%.
Escape Bombs and Spirit Weapon Awakening will also ignore monsters' protection.
If you manage to splash attack an enemy and a Critical occurs, then all the targets will receive critical damage.
Any "Area of Effect" (AoE) attacks also apply to this formula.
If the user successfully performs a Critical Hit, it will make the stunning effect longer but it cannot be a knock back attack.
The Critical Hit skill affects all forms of critical hits, including those from magical attacks.
Landing a critical blow to a monster will reset the monster's action to what it was doing beforehand.
Critical blows can change Aggro.
If Passive Defense is triggered by a critical hit, the monster will still be stunned regardless of its passive defense level.
Skill cannot be used at Novice Rank, regardless of what Critical % Chance you have.