Reactive Casting allows a caster to begin a spell (and perhaps complete it) as a defensive action if he is not already casting a spell (though the current spell can be abandoned in desired). The mage’s turn is moved in the turn order to the current turn position and his turn occurs immediately, as in the case of a prepared action. This ability can be useful for countering actions with quick spells, casting defensive spells against enemy attacks and spells, healing an ally in the nick of time, or simply getting a jump on starting a spell when changing conditions make it clear that the spell is needed. It is a favorite ability of duelist mages, but can be useful for other kinds of mages as well.
Magic-users and Battle Mages primarily get Reactive Casting. Characters who cast magic in the midst of battle can make a good case to get it as a cross-class ability.
Would you play a character who can engage in melee combat while also casting spells? What kind of considerations would you have to make? Comment below to let us know.