You've 9 Feats. So compare yourself to a Human fighter wielding a greatsword at 12th level.
1st HD: Weapon Focus: Greatsword
Human: Improved Toughness
Fighter 1: Dodge
Fighter 2: Power Attack
3rd HD: Whatever
Fighter 4: Weapon Specialization: Greatsword
6th HD: Whatever
Fighter 6: Whatever
Fighter 8: Improved Critical: Greatsword
9th HD: Overpowering Critical (+4 to confirm threats)
Fighter 10: Whatever
12th HD: Greater Weapon Focus: Greatsword
Fighter 12: Greater Weapon Spec: Greatsword
This guy will have a +14/+9/+4 to hit you on your round, before you consider his STR bonus, or how much he Power Attacks. On a hit, he will do 2d6+4 damage, plus STR and a half. He will have 12 more hp than you do due to Improved Toughness. He will crit 20% of the time, and then do 4d6+8 damage. His AC will better your non-Expertised/non-karmic striked AC by 1.
Meanwhile you will do 1d6 damage to him... 6+STR is your max damage. 6+STR is his minimum damage.
You will attack him 6 times at most in a round... 3 from your BAB, and 3 if he hits every time. So if you hit each time he will take 6d6 points of damage. But that's only if he hits 3 times, and if he does, you will be taking 6d6+12 points of damage...
See where this is going?
You can only get off 6 attacks if you:
A) Lower your AC through Karmic Strike (I assume the penalties to AC are cumulative?)
B) Lower your to-hit through Combat Expertise to shore up your AC
So, if you take option A, a good fighter will notice this. On the second and third rounds of fighting he will Power Attack, getting him 2 more damage per 1 to-hit given up. Power Attack is efficient when fighting low-AC monsters. Which is what you turn yourself into by choosing option A.
If you take option B, you will reduce your chances of hitting him (His AC isn't going anywhere), and you might not even do 1d6 point of damage!
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Yes, what you have is a fun little combo that ties a whole slew of feats in together with the spiked chain, which is a novelty weapon. But it is a sub-standard weapon, and while it lets you do neat tricks with it, the feat input necessary to make it combat-viable renders it underpowered. This fighter has 9 feats to his credit, as does yours. He is built for combat, but then, isn't every class supposed to be balanced against a fighter of equal level?
Your feat selection turns you into a less-than-effective one-trick-pony, though it is terribly flavorful.
Sorry.
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PS, I read your other thread Tilla the Hun, and noticed that you called your DM a Rules Lawyer. I heretofore issue an injunction against you ever calling him a rules lawyer again; I am one and a certain degree of knowledge of the rules is expected before you get your degree in Rules Lawyering. He doens't have that knowledge.
