When wielding a blunt melee weapon, you can make an attack that leaves your opponent unconscious.
Prerequisite: Weapon Focus (any blunt weapon), swear an oath to preserve life, even that of your enemy, at any cost
Benefit: When attacking a living target with a blunt weapon with which you have Weapon Focus, you take no penalty when attempting to deal nonlethal damage. When you make a critical hit with this weapon or a successful hit against a living target who is flat-footed or otherwise denied their Dexterity bonus to armor class, your opponent must make a successful Fortitude save (DC 10 + half your character level + your Strength modifier or Dexterity modifier if you are using the Weapon Finesse feat) or be rendered unconscious.
Special: If any attempt is made to kill this helpless opponent, the opponent is awakened and takes his turn immediately as if it were his turn in the initiative order. If you break your oath (GM adjudication) or do not attempt to prevent the murder of your captive, you lose all benefits of this feat. Creatures immune to critical hits are immune to this effect.