This is our proprietary skill rating calculation. This has nothing to do with official game ranking or MMR.
The purpose is to show player skill levels relative to other players, not estimate MMR.
PASSIVE - Melee Basic Attacks decreases enemy Physical protections by 7, and increase your physical protection by 5 for 3s (max. 2 Stacks).
PASSIVE - Your Critical Hits provide you with 10% Physical Penetration for 4s.