Blood-Sucking Weapon

Blood-Sucking Weapons are a type of weapon mass produced by the Dragoon Laboratory for use in Operation: Jacob's Ladder. While the weapons vary from blades and bows to more modern armaments such as pistols and shotguns, each is identifiable by the stylised cross emblazoned on it. When a demon is killed with these weapons, their blood is absorbed into it in the form of red glints of light which strengthens the weapon.

When a certain chant is used, the collected blood can later be released from the weapons.

History
It is revealed to Ryuji Suguro that the weapons are similar to a sword once used by a Transylvanian Count, implying that they were based off of it in design.