Lanthalas Strike

Lanthalas was an Elven Paladin of Tyr who wielded a Great sword with considerable strength and power.  Bards would say his blows were so powerful it could kill some creatures in a single blow.    Strength requisite of 16 required for this feat.    +1 to hit modifier;   On a roll of 19 it scores a Critical Hit;  On a roll of 20 it scores a Critical Hit and creature of medium or smaller size is stunned till the end of their next turn (Save vs STR.)