Changes

Casting in combat is difficult, since making sure that you cast the spell right often means that you leave yourself open for a moment. It takes focus to do both, and the more deeply you understand your magic the more easily you can do so. As part of the action to cast an arcane spell, you can attempt to cast it defensively.</onlyinclude> This check is rolled once, and the result used against the DC for each opponent threatening you in melee. The DC for each opponent is 15 + the spell level + your opponent's base attack bonusor CR, whichever is lower. Additionally, and you suffer a penalty to this check equal to the number of foes threatening you minus one.