Cleave

You have learned that a powerful enough swing of your blade can be carried through one opponent into another.

If you deal a creature enough damage to make it drop (typically by dropping it to 0 hit points or killing it), you get as a free action a chance to transfer any residual damage from the first target to another creature within range of your melee weapon plus an additional 1d4 slashing damage + your Str Modifier. You cannot take a 5-foot step before making this additional strike. The strike is with the same weapon, and a roll below their AC means they absorb the extra damage. You can use this ability only as a free action on your turn directly after an attack action.