I am an expert because I have seen the code. Mastery of pain makes a
substantial difference, tho not nearly as much as, say, fire mastery on lava
blast. Why mastery of pain? Well, the spell _is_ a harming spell, with all the
usual benefits (it is not resistable as fire or phys damage is) and benefits
(it can't kill anyone). And it does cause a lot of pain, so mastery of pain
would seem pretty appropriate.

But why is the mastery in another guild? It's guild synergy. It's like locs
having parry and tigers having dodge, not that impressive individually but
very potent together. This is simply another such example.

Also, the spell is pretty strong without the mastery. Consider the mastery an
added bonus for having a specific guild combo. It's hardly the only such combo
out there.

Shinarae Lluminus