This paper model is a full size Blue Rose, Nero's personally designed long-ranged weapon, based on the action-adventure hack and slash video game Devil May Cry, the paper model is created by Sinner. The size of finished model is about 188 (H) x 450 (W) x 63 (D) mm.
It is a unique revolver with an over and under barrel style, this design allows it to fire two magnum rounds with each pull of the trigger. Nero is the only member of the Order of the Sword known to wield a firearm because they believe guns to be dishonorable. [Source: wikia]