15 years ago or so I caught most of an anime movie on tv. It starts with an explanation about how they proved magic exists and starts using it to power everything. When people are exposed to it wrong they turn into these giant visceral monsters and the main character is one of the guys they send in to kill the monsters. There was an emphasis on sigils, the main guy has thus witch girl that paints his magic sigils on him, and I vaguely remember sigils around the muzzles of their guns?

Does anyone know the name of this? I never caught it back in the day and it pops into my head every now and again.