Aggressive Magics were used only during the Six Planets war, which occurred from 2965 through 3006 and involved the two planets of Imdlemodin and Charth who invaded the four planets of Coda, Nojura, Halo, and Mant. And while Imdlemodin and Charth were the invaders and perpetuators of the fifty-one year long war, it was the Four Planets that had the capability of creating and using aggressive pentrinsic programs.

The price for using an aggressive spell was high for the muser: Greatly increased instances and vividness of nightmares, loss of connection to humanity, crippling, lifelong guilt. The price was even higher in the war; of the 821 students trained to use aggressive magics by Kerri Marks, 717 were killed during the war. Of the 104 who survived, sixty-two committed suicide and another twenty-eight were institutionalized at some point in the years following the war. Kerri Marks, herself the most cold and ruthless of the attack musers, suffered severe depression and ferocious nightmares well into her sixties.

While any program - or spell - could be used in an aggressive fashion (using Teleport to move an object in order to damage or destroy it), there were a limited number of spells that were certain to exact punishment on the muser. Below is the only known compiled list of "absolute aggressives", or spells that will always have a negative impact on the muser, regardless of race.