Magic Formula

Ars Magus (術式) is the use of science to manipulate seithr. The knowledge for how to perform each ars is recorded in a Grimoire.

Information
During the Dark War, Konoe A. Mercury of the Six Heroes passed her sorcery to mankind but humans were unable to use it in its basest form as they were not capable of handling or manipulating it. Therefore, in order to make use of it, humanity did a great deal of research into the subject and eventually developed what is now known as "Ars Magus". By using science to manipulate seithr that came from the Black Beast, ars magus could be used to many ends. In order to use ars magus, one would have to recite the ars, or "spell". When ars magus was first developed, the creators found that the power and effectiveness of a grimoire varied with its user. Since that discovery, mankind was able to produce more efficient ars magus. Unfortunately, Ars Magus alone was not enough to defeat the Black Beast and mankind knew they would need more power and developed Armagus and Ars Armagus.

It was completed approximately within half a year, thanks to Yūki Terumi's massive knowledge of seithr and the Black Beast. As normal people do not posses the ability to manipulate seithr, a Grimoire, a type of converter, changes the gathered seithr within the Ars Magus.

Ars Magus Aptitude test
The Ars Magus aptitude test (術式適正) is a simple test that is based on Ars Magus synchronicity. The test itself consist of activating a base Ars Magus. The aptitude is measured by the amount of seithr that the tester requires to activate it. An average person requires 20 units of seithr for the activation, while someone like Taokaka needs only 10.

These tests are carried out in the Military Academy while assessing new students; Noel Vermillion has the highest recorded synchronicity.

Trivia

 * In English version of BlazBlue: Calamity Trigger and BlazBlue: Continuum Shift, Ars Magus is called also as "Armagus".