Simple - Half orc fighter with high strength equipped with:
- (improved) power attack
- weapon specialisation scythe
- all ability points pumped into STR
- improved critical scythe
- Eventually take the weapon master priestige class focusing on the scythe for 10 levels or so
- Overwhelming critical scythe
This basically means that with a +3 scythe you could dish out:
(2D4+3)+2+10+10 = 27-33 damage per hit with Improved power attack and 25 STR
or quite easily...
(2D4+3)+2+18+10 = 35-41 with 35 STR.
The clever part is critical hits - criticals would be rolled on 17-20 with a keen scythe and (taking 35 STR as an example) deal out (((2D4+3)+2+18+10)+4D6)*5 =
195-325 damage.
That's strong enough to take out dragons on a single blow! Who needs devastating critical eh?
I'm sure there's a way to figure Barbarian into the equation along with thundering rage to boost this critical damage even higher!