Frost

Gives the Champion a 20% chance to use the [Freeze] debuff for 1 turn when attacking an enemy Champion. Unlike most other sets, the Frost Set applies the [Freeze] debuff when the wearer is attacked by an enemy, rather than when the character attacks someone. This means that the set is best used on champions who are frequent targets for the enemy team, such as with debuffs [Provocation] or [Mockery]. This makes every attack of the enemy champion risky.