Dealing Ability Score Damage as a PC

[Haveatya]

I want to make a character that deals ability score damage really, just an idea i had. Whay are some ways to do it?

So far I got the neckbreaker line and.....and well that's all I know honestly.

Help would be appreciated

[Korak The Boisterous]

Brewmaster from Interjection games is capable of it with the right build.

[FLite]

Giant Weasel familiar deals con damage, really, really, really slowly

Poison

Various spells.

[Ms. Pleiades]

You'll want a 9th level spellcaster like the witch or wizard. Arcanists do it rather well too. Make sure you work to target all saves and as many different stats as you can.

[lemeres]

Well, shadow dancer is also a way (depending on how you count 'pc'; ie- through a resource under your power with the shadow doing lethal str damage)

...but most likely not what you were looking for, right?

Also not in the right place, but still an interesting fact- stirges are on the summon nature's ally 1 list. They attach the the enemy, and deal 1 con damage at the end of their turn when they are attached. Then they fly off after 4 con damage.

Stirges are not strong though...which is an advantage. Con damage is a huge threat, and not dealing with it is a terrible idea when it is so easy to solve. Stirges can be killed by pretty much any single attack when talking about higher levels. But you can summon 1d4+1 (plus whatever from summoning specialization). Target fire on one opponent, and they are almost guaranteed to take at least a bit of con damage. And they are guaranteed to be distracted for a while, which is also great.

[FLite]

Various barbarian rage powers, starting at level 8 or so. Crippling blow, disembowling fist, so on.

(Also, Cairn linnorm death curse, but that is 1 con damage a day, and you have to lose the fight first. Probably not what you are looking for.)

[Covert Operator]

In terms of Martials:
Rogue with the Ninja Talent that lets you deal 1 STR or DEX damage with eery sneak attack
Poison
Wolf Savage (style chain based on tripping) lets you Bestow Curse if they're prone and you deal 10 damage with unarmed/natural attacks.

It would be possible to combine all of these to then trip via Maneuver Master, do 2 poisons +2 STR damage with a TWF full-attack, then use Wolf Savage all as a full-round action.
You could take Major Magic: Touch of Gracelessness or Ray of Enfeeblement
This is a relatively solid build, although it might have some gaping holes I missed.
I think you should go the natural attack route for this build, on second thought.

Watch your opponents become vegetables crushed under the weight of their own backpacks.

On an unrelated note to this build:
Cleric's alt channeling has options to (I think) deal damage to any physical stat or intelligence, which are two different alt channels. Add Touch of Idiocy.
There's a unique trident magic item that deals DEX damage something like 7 times per day.
Something to do with calcifying flesh.

[Imbicatus]

Calcific touch spell is a good way to deal dex damage.

[LazarX]

I believe there's at least one feat or rogue talent that lets you trade in sneak attack dice for ability damage.

Poisoning your weapon also works.

[Covert Operator]

If you want to do poisons, I saw somewhere that you could put inhaled poisons into a smokestick and use alchemist or rogue to get a slow metabolism so you can hold your breath while your enemies wither away and die just for standing near you.

[kestral287]

Swashbucklers and Gunslingers can do Str, Dex, or Con bleed.

Realistically though the answer is "casters".

[Covert Operator]

To add to my build above (focused on dealing STR damage):
Ring of Strength Sapping

A rogue can take these for rogue talents:
Ninja - Pressure Points and Advanced Talent - Crippling Strike

Lots of rage powers

If you and your party can get immune to poison, carry around Irradiated everything

Racial Heritage (Frost Giant) --> Born of Frost --> Icy Stare

Main weapon for the build: Rod of Withering deals 1d4 STR and 1d4 CON damage instead of normal as a touch attack! Deal Sneak Attack on a touch attack with Deliquescent Gloves (touch attacks deal 1d6 acid damage), or a Runefrost Hatchet instead if you still want to deal weapon damage.

Shadow Projection
Chill Touch level 1 spell can be used by a Rogue with the Major Magic talent.

Aaaand that's about it. Looks to be shaping up as a pretty good build at level 10+
Obviously you aren't going to take all these abilities, but grab a bunch.

[zza ni]

1st bloodlin ability of the nanite bloodline

beside being a sorcerer,it can be gained via the eldertich heritage or by going vmc,sorcerer .(which give out other benefits,but cost 5 feats) this is nice as the dc and effectivness goes up with your level. and by level 11 you get a "posion" that has :

"Poison—injury; save Fort DC 10 + 1/2 your sorcerer level + your Con modifier; frequency 1/round for 6 rounds; effect 1d2 Str damage + 1d2 con damage; cure 2 saves"
usable for 3+cha mod\day