Keen effects for weapon, feat and WM?

[Ahku]

Hello all!

I know i may have seen this on the site, but i cannot find it:

What i would like to know is what stacks with the effect from a weapon with the keen ability?

Does the feat 'improved critical' stack?

Does the weapon master's 7th level skill 'threat range' stack?

I am building a fighter / weapon master that will have 'perfect 2 weapon fighting' at 21st level!
His name is 'Bartimus' - say hello!

thanks,
~Ahku

PS: It is INSANE how many feats a fighter gets!

[Blackman D]

WM stacks with everything

keen spell and feat improve crit do not stack with each other

so if you are a WM you only need one or the other