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 - For every non-ultimate ability on cooldown you gain a stack of Cruelty. Each stack provides 7 Physical Power and 2% Physical Lifesteal.
PASSIVE - Your Critical Hits provide you with 10% Physical Penetration for 4s.
PASSIVE - Enemies hit by your Critical Strikes have 40% reduced healing for 5s.