How does a brawler’s knockout ability achieve making an opponent unconscious?

[feng shui]

The Knockout ability instantly renders an opponent unconscious if they fail a fortitude save after taking damage from a declared attempt. The unconscious condition “can result from having negative hit points (but not more than the creature’s Constitution score), or from nonlethal damage in excess of current hit points.” Does this mean that the Knockout ability, if done with a lethal attack, drops the creature to -1 hit points?

I’ve been arguing about this on Reddit and would love a rules clarification if possible.

[Kimera757]

Quote:

At 4th level, once per day a brawler can unleash a devastating attack that can instantly knock a target unconscious. She must announce this intent before making her attack roll. If the brawler hits and the target takes damage from the blow, the target must succeed at a Fortitude saving throw (DC = 10 + 1/2 the brawler’s level + the higher of the brawler’s Strength or Dexterity modifier) or fall unconscious for 1d6 rounds. Each round on its turn, the unconscious target may attempt a new saving throw to end the effect as a full-round action that does not provoke attacks of opportunity. Creatures immune to critical hits or nonlethal damage are immune to this ability. At 10th level, the brawler may use this ability twice per day; at 16th level, she may use it three times per day.

From Color Spray

Quote:

A vivid cone of clashing colors springs forth from your hand, causing creatures to become stunned, perhaps also blinded, and possibly knocking them unconscious. Each creature within the cone is affected according to its HD.

There's no damage, and no -1 hit points.

The ability works the way it says it works. The target is rendered unconscious until they make their saving throw or until the duration is exceeded. It's pretty similar to being knocked out by a Sleep spell or a Color spray spell. It's powerful, as you could defeat an opponent at full hit points instantly (unconscious means easy CdG), so you can't use it too often.

[Melkiador]

Those are just examples of situations that can cause the condition. It’s not meant to be an exhaustive list.

[Meirril]

There are rules for circumstances that cause a condition. Having more non-lethal damage than hp, or being reduced to negative con hp both are circumstances that lead to conditions (unconscious and dead respectively).

That doesn't mean there aren't other ways to get those conditions, or that the condition causes the circumstance. Like if you are killed by a death effect that doesn't cause hp damage, Breath of Life won't fix the dead condition even if you cast it in the time limit because the target didn't gain the dead condition by losing hp. Breath of Life explicitly mentions this!

Also Raise Dead and other spells that remove the dead condition specify what your hp will be like when the target is revived, but nothing about the cause of death. What gave the condition doesn't matter. The same applies to most spells that remove a condition.