QUOTE(shiki666 @ Apr 21 2012, 01:43)

what does increase elemental/holy/etc damage % on the ability tree?
Nothing. You'll need EDB Phase for that .
QUOTE(shiki666 @ Apr 21 2012, 01:43)

When I use Soul Magic does it increase my Spiritual Proficency?
No, Spiritual is simply the average of Divine and Forbidden.
QUOTE(shiki666 @ Apr 21 2012, 01:43)

Finally is it possible for a level 180 mage to beat FSM on IWBTH?
I guess it is with some preparation, but I don't see the point.
99 times out of 100 you won't get anything good out of it, and doing it without Spirit Shield just complicates everything.
I'd wait to get a decent Heimdall set if I were you.
QUOTE(shiki666 @ Apr 21 2012, 01:43)

Adding up all the numbers for the whole set makes my Dark mitigation 105.96% does that mean FSM's normal attacks won't even do any damage??
They're added multiplicatively, so you would get 1-(1-0.2102)*(1-0.2534)*(1-0.2073)*(1-0.2231)*(1-0.1697) = 0.69 = 69% dark mitigation.
It would still rape you with physical attacks though.