Grants the racial ability "you are given physical damage reduction" which gives you a 10% reduction in incoming physical damage. It is unknown currently where in the process this reduction this is applied. (e.g. before PV% and dice roll or after.)
At least known in Elona+ version 1.37, the physical damage reduction happens after dice roll and PV effects, but to some extent of disappointment, the amount of physical damage reduced seems to be only one point. A 10% damage reduction is only given when you believe in Opatos of Earth. This damage reduction is valuable as it happens just before your HP is affected by the damage and comes in the last step of damage calculation, so it is actually not only a form of physical damage reduction.