An Event Weapon Imitation (模倣事象兵器 Mohō Jishō Heiki, localized as Artificial Causality Phenomenon Weapon) is a non-magical imitation of the Arch-Enemy Event Weapons created through advanced technology. These devices rely on atomic power rather than Magic Element to function. The Idea Engine is an improved version of these devices. These weapons create a resonance effect in proximity to a true Arch-Enemy, as it "recognises it as something similar to itself". These were made by Kokonoe after her study of the Machine God: Nirvana. Overall, the weapons aren't as powerful as Arch-Enemies, however.
Iron Tager is known to possess (or be) one of these weapons, while Ex Machina: Minerva is one itself. Lambda -No. 11- possessed a more powerful version of the weapon called the Idea Engine; she gave it to Ragna the Bloodedge as she died. Arakune is also in possession of a weapon as Relius Clover installed it into him; Relius also created the Detonators which use an Event Weapon Imitation as their base.