Iron Maiden is a forbidden type of magic that is unique to Ruby Toujo.
Use:EditRuby's talismans wrap around her body before transforming into body armor. As revealed by Ruby, it isn't an ordinary armor, as it raises every stat the user has. However, by doing this, it causes an abnormal strain on the user's body that is enough to break tendons and tear muscles.
Ruby has also shown to be able to extend the gauntlets covering her arm and fire extended bandages or feathers at an enemy with it. She has also shown that she can use the bandages to quickly wrap around an trap an enemy.