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 - Your Critical Hits provide you with 10% Physical Penetration for 4s.
PASSIVE - On damaging an enemy god with a Basic Attack, gain 2 Physical Pen for 5s, stacks up to 3 times.