Demon Guns: Bolverk

Arcus Diabolus: Bolverk has the shape of a pair of handguns. According to Continuum Shift, it can attack targets through walls, Type XI: Optic Barrel being a dimensional collapse of sorts at a point in line with the barrel. Bolverk also serves as a limiter for Noel as it suppresses her emotions. This explains why she does not become emotionally unstable as Carl Clover or Jin Kisaragi. It is also revealed that in Noel's past she was attacked by a monster and suddenly Bolverk appeared right before her. In Continuum Shift's True Ending, Noel's emotions broke Bolverk, unleashing Mu-12. Bolverk is later restored in Chronophantasma. It is currently unknown how it was restored, although it is possible that it simply overloaded for a time.

During the Dark War, Bolverk had a multitude of owners, including one of the Ten Saints; Three. After their death, Bolverk was given to so many owners over time, its location eventually became unknown to even Jubei until it's possession by Noel Vermillion.