Can someone explain what are the exact effects of the 3 attributes? STR surely affects damage and encumbrance, maybe VIT, but what about DEX and INT (the latter doesn't even seem to be mentioned in the "Magic section" of the manual, but maybe I missed it). Thanks.
I'm not sure about the exact equations, but here is a general guide: http://wiki.ultimacodex.com/wiki/Character_attributes
STR determines the overall carrying weight, with double STR being the weight the Avatar can carry. STR also factors into the calculation of the damage a weapon does to an enemy in combination with the attack and weapon skills.
DEX, together with weapon skills, determines the hit chances, and with the defense skill, the evading chances.
INT, together with the mana skill, determines the mana pool, and with the casting skill, the chance of a spell being successfully cast.