Many of the demons are aggressive, specializing in power amplification and weapon enchantment.
The death rate of those who challenge Black Demons is exceedingly high compared to other Demon Weapons. Not many people are capable of wielding a Black Demon weapon. Anyone who is a candidate for the Black Demon Series has been experimented on, but these candidates are exceedingly difficult to create. Successful candidates are even more rare. Anyone bearing this rank of weapon can easily kill multiple vampires armed with second-class weapons.
There are eight that have been named so far.
A sword-gun type of Cursed Gear contracted to Major General Shinya Hīragi. Its bullets appear as white tigers, and it may fire one shot that appears behind its target.
A bow-and-arrow type of Cursed Gear contracted to Special Private Yoichi Saotome. It provides its bearer with the ability to see great distances, and it can fire bird-like arrows at multiple targets simultaneously.
A sword type of Cursed Gear contracted to Special Private Yūichirō Hyakuya. It has a special ability called Asura-Kannon that materializes an array of swords behind its bearer.
A twin sword type of Cursed Gear contracted to Special Private Shihō Kimizuki. It has a special ability that materializes and opens the devil's coffin on the count of nine.
A sword type of Cursed Gear contracted to Lieutenant Colonel Guren Ichinose. The demon was his lover when she was a human. It is the result of Mahiru being absorbed by the Noya curse. Mahiru-no-Yo powers depends on the demons power. If Mahiru and Noya separated it can turn the host into a Namanari. However the sword still remains, it grants the host tremendous power and speed. Mahiru-no-Yo can return to Guren hands if the sword is away, as well as command it.
A sword type of Cursed Gear contracted to Lieutenant Colonel Guren Ichinose. It has a special ability to grant the host immense strength and power as well as enhanced healing and senses while filling them with desires. The more desire his host has, the greater his power becomes. The demon's transformed into Mahiru-no-Yo after the Noya curse absorbed Mahiru, with all it's abilities as well.
A sword type of Cursed Gear contracted to Lieutenant General Kureto Hīragi. It covers its bearer with electricity. The more desire the host grants the more extensive, speed the host gains and more powerful the electricity it produces.