I couldn't finish 'em. Looks like this's gonna get complicated.
The Fire Materia is an enemy in Crisis Core -Final Fantasy VII-. Sephiroth summons it, along with the Thunder Materia and Blizzard Materia, to defend himself and to attack Zack with the magic that they represent.
Fire is the rapid oxidation of a material in the exothermic chemical process of combustion, releasing heat, light, and various reaction products.
Materia means "matter" or "substance" in Latin and Spanish. It also means "subject" in Italian and Spanish, and is the ascendant of Portuguese "Matéria".