So let's give this a try.
Mind you, this one will be focused on max level damage and thus include a few items.
Fighter - Archetype: Two-Handed Fighter
Stats - Human - 20pt buy:
Str - 48 (= 18 + racial (2) + character level (5) + "Belt of +6" (6) + Orc Bloodline SotB (6) + Orc Bloodline PoG (6) + Manual (5) )
Con - 14
Dex - 14
Int - 7
Wis - 7
Cha - 17 (= 11 + Headband of +6 (6) )
Trait:
Opportunistic Gambler
Feats
1 - Exotic Weapon Proficiency (Tetsubo), Power Attack, Skill Focus: Survival
2 - Weapon Focus: Tetsubo
3 - Furious Focus
4 - Weapon Specialization: Tetsubo
5 - Eldritch Heritage (Orc Bloodline - Touch of Rage)
6 - Vital Strike
7 - Combat Reflexes
8 - Greater Weapon Focus: Tetsubo
9 - Devastating Strike
10 -
11 - Improved Vital Strike
12 - Improved Eldritch Heritage (Orc Bloodline - Strength of the Beast)
13 - Greater Weapon Specialization: Tetsubo
14 - Improved Devastating Strike
15 - Improved Devastating Strike
16 - Greater Vital Strike
17 - Greater Eldritch Heritage (Orc Bloodline - Power of Giants)
18 - Penetrating Strikes
19 - Greater Penetrating Strikes
20 -
Now, to round out your magic items:
Some kind of ring/amulet/whatever fits to give you Lead Blades. Or just spending your limited skill points in UMD so that you can wand it onto yourself.
Something to give you the Deadly Juggernaut Spell. Perhaps another wand or maybe just the Juggernaut's Pauldrons?
Gloves of Dueling, of course.
A +5 Impact Courageous Thundering Tetsubo.
Now, these will be the relevant class features:
3 - Overhand Chop (Double Strength Damage Bonus to 2h-weapons when making a single attack with the attack action)
- - -
5,9,13,17 - Weapon Training +4 (+6 with them gloves)
- - -
15 - Greater Power Attack (+100% damage from Power Attack when using a two-handed weapon instead of +50%)
- - -
19 - Devastating Blow (standard action which, by suffering a -5 penalty to hit, allows you to make an attack that automatically critical threats on hit)
- - -
20 - Weapon Mastery: Tetsubo (Oh come to papa, auto confirming critical threats and also increasing the critical multiplier by 1)
There will be a few big points in the development of this character where your damage receives a spike.
The first will probably come when you get Impact on your Tetsubo.
The second will likely be when you can reliably get Enlarge Person and Lead Blades on yourself.
A few others will be the Greater Power Attack, Greater Vital Strike, and so on.
But the largest one will be at 20:
Enter Devastating Blow + Weapon Mastery: Tetsubo
This should hit for:
4d8 + 5 (Tetsubo) + 38 (doubled Str bonus) + 5 (a continous Deadly Juggernaut) + 7.5 (Touch of Rage) + 2.5 (Courageous) + 6 (Weapon Training) + 4 (Greater and normal Weapon Specialization) + 20 (Greater Power Attack) = 4d8 + 78 = 96 points of damage per average normal hit.
If we want to we can simply add 12d8 + 6 to represent a Greater Vital Strike which would make a Greater Vital Strike hit land at about... 156 on average. Not bad, but we can do better.
For this was a crit with a Tetsubo and we happen to be Tetsubo Weapon Masters.
Thus Crit Multiplier = 5
An average hit would strike at 480 damage. With an additional 5d8 from Thundering so... 502.5 points of damage.
And if we happen to have someone nice in our party whom built Butterfly Strikes...
...
502.5 + 6x5 + 12d8 = 568.5 points of damage.
Huh, that's enough damage to instantly knock the Tarrasque unconscious, and prevent it from regenerating in its second round...
So a lvl 20 AVERAGE of 502.5 per hit and round on his/her lonesome, an average of 568.5 per hit and round if helped by a teammate with Butterfly Strikes.
Is this sufficient?
P.S.
The open feat-spots were to be filled by the feat line that prevents opponents from withdrawing and all that, assuming 3-4 spots is enough for that?