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.
AURA - Allies within 70 units receive 10 Physical Protection and 10 Magical Protection.
PASSIVE - You gain additional Magical Power and Lifesteal scaled from missing Health. This caps at 70 power and 10% Lifesteal at 40% Health.