so im making a natural attacker for a game im in that allows third party classes/archetypes so im wondering does the warpriest dmg from sacred weapon act differently then from unarmed strike increase dmg from monk ?
Punctuation, man - PUNCTUATION!!!
Anyway, yes and no.
A Monk's scaling Damage is for Unarmed Attacks alone.
A Warpriests' scaling Damage is for ANY weapon with which you have Weapon Focus OR is your Deity's Favored Weapon. ALSO, a Warpriests' scaling damage is based on the size of the Warpriest, not on the size of the Weapon (so no Large Weapons, sadly, and Impact is just COMPLETELY useless as an Enhancement Ability for you).
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For Natural Attack builds, you can take Martial Versatility, which will give you Weapon Focus with all of your Natural Weapons.
Once you have access to a Natural Weapon, enter into Warpriest to gain Weapon Focus with that Weapon.
At Warpreist 3, take a generic Combat Feat as a filler for your Bonus Combat Feat; at Warpriest 4, Retrain your Bonus Combat Feat to be Martial Versatility.
The reason you do this is that your Warpriest levels count as Fighter levels ONLY for Bonus Combat Feats; so your 3rd level BCF looks at your Warpriests levels at lv4 and counts them as 4 levels of Fighter, which is what's needed for Martial Versatility.
From that point on, ALL weapons in the Natural Weapon Category gain Weapon Focus INCLUDING Unarmed Strikes
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Since you'll want to focus on multiple Natural Weapons, you actually don't want to take a base Warpriest, and taking Sacred Fist is just a waste of time for you, honestly, because of how Feral Combat Training got utterly destroyed with the errata (You'd have to charge each and every Natural Weapon separately with Sacred Weapon's enhancement ability, and spend 1 Round per Weapon, meaning you'd eat up rounds very quickly).
Instead, you want to be a Champion of the Faith.
CoF Warpriests trade out the lv4+ ability to apply Enhancement Bonuses and Abilities to your Sacred Weapon, and instead gain a Smite ability, plus the ability to naturally grant the weapon the Holy/Unholy/Axiomatic/Anarchic Enhancement Ability to your Weapon.
This is better for you because you retain the Scaling Damage of Sacred Weapon (just not the Enhancement sub-ability), and Smite applies itself to ALL Attack and Damage Rolls made during a Smite, meaning every single Natural and Unarmed Attack you make is going to get a Bonus to hit (that STACKS with Enhancement Bonuses) equal to the Charisma, and a Bonus to Damage equal to your Warpriest level.
In short, whatever you are targeting for your Smite is going to be reduced to a fine red mist in very short order.