Anti-Magic is a force within the world of Trinity Seven.
Anti-Magic is generally used to protect against or counter magic. Generally things like crystals and mirrors will reflect magic.
Both Arata and Mira use this magic. Anti-Magic is both used to deflect magic and destroy magic. While Mira uses it both as a form of defense and offense, Arata uses his anti-magic exclusively offensively using the magic to dispel other magic or destroying anything magical. However it does have the side effect of dispelling anything magical including clothes which are magical in a way. Anti-Magic can also be use to repel other Anti-Magic.