Cursed Gear

Cursed Gear (鬼呪装備) are weapons in Seraph of the End used by the Japanese Imperial Demon Army.

Despite having immense power, Cursed Gears also carry a great risk as well since there is a high chance that whomever uses one will either be possessed by the Demon inside at best, or becoming a Namanari at worst; should this occur, the Japanese Imperial Demon Army's standard routine is to kill the rampaging user immediately.

These weapons were developed during the Seraph of the End: Guren Ichinose: Catastrophe at Sixteen light novel series and plays an important role in Seraph of the End: Vampire Reign manga series.

Creation
Cursed Gear are created by directly calling upon a Demon and then sealing them inside of sacred items, usually weapons like swords, axes or bows, using a Demon Curse (鬼呪) so they may serve the wielder. However, in order for a weapon to become a sacred item, it needs to be consecrated and purified - a long and strenuous process that can take years before it's able to contain a Demon.

However, once properly created, Cursed Gear can increase a normal person's capabilities sevenfold. In fact, the power of Cursed Gears was great enough that it not only managed to revolutionize the world, but it also caused traditional forms of magic to fall into disuse as well.

There are multiple rankings for Cursed Gear, with the lowest-ranking ones enabling their wielder to fight on par with a Vampire using a Second-Class Vampire Weapon. Compare this with the highest ranked Cursed Gears, the Black Demon Series, which can grant anyone who bares them enough power to kill multiple Vampires armed with Second-Class Weapons.

Enchanted Gear
Enchanted Gear (呪術装備, Jujutsu Sōbi) (which Yūichirō Hyakuya uses in Chapter 2 of Vampire Reign) is a weaker, mass-produced version of Cursed Gear; usually being at around "Yaksha" or "Myo-O" level in terms of power. Using one of these, a regular human's capabilities would increase by three to four times, allowing seven humans armed with to kill a single unarmed Vampire. However, even an entire unit would still be hardpressed against even one Vampire with a Second-Class Weapon. Also, unlike that of Cursed Gears, Enchanted Gears can still be broken by stronger weapons.

Manifestation
Manifestation (具現化) is the state in which the user lets his or her contracted Demon come out so as to use their special power, this drastically reduces the defensive abilities of the host since the Demon moves elsewhere. These types of Demons work best at different ranges and the type of ability varies. They also have the ability to disappear and reappear at their user's command and some of them even have the ability to manifest on their own will, such as Byakkomaru and Shikama Doji.

Examples of Manifestation-type Demons include: Shikama Dōji, Gekkouin, Byakkomaru, Kuronagi, Akahebi, Genbushin, Kakuze, Sankoujitsu, and Tenjiryū.

Possession
Possession (憑依化) - Demons have malice that's too strong, making them highly aggressive and ferocious, hence they refuse to submit easily and often try and possess their user. Due to their pride and combativeness, it's common for these kinds of Demons to engage in direct combat to display their might. Also, a result of the high levels of malice they emit, these Demons are very hard to summon or dispel. While these normally Demons don't have special abilities like those seen in Manifestation-type Demons, are have been a number of special cases, such as with Asuramaru and Kiseki-o.

Examples of Possession-type Demons include: Asuramaru, Kiseki-o, Mahiru-no-Yo, Noya, Kukuri, Kagutsuchi, Raimeiki, and Demon Mika.

Black Demons
The strongest Cursed Gears due to containing first-rank Demons, very few people are capable of wielding them, with only those who've been experimented on previously being capable of such. Anyone bearing this rank of weapon can easily kill multiple Vampires armed with Second-Class Weapons.

The death rate of those who challenge the Black Demons is exceedingly high compared to other Demon Weapons, with only those with strong willpower and resolution are able to challenge them.

The users must undergo operations to significantly alter their minds and bodies. They must also understand the demon's curse, have a strong ability to control magic, and have the right disposition for controlling a demon. Even so, the success rate is less than 20% in the Catastrophe light novels. Guren catches Kureto Hīragi's attention when he has three teenagers successfully wield black demons in the manga.

Bodhisattva
No information. Known demons: Kakuze.

Rakshasa
No information. Known demons: Genbushin, Kagutsuchi, Kuronagi.

Dakini
No information. Known demons: Tenjiryū, Kukuri.

Fiends
No information. Known demons: Akahebi.

Wisdom Kings
Cursed gear from the Wisdom Kings Series and above are used by the Vampire Extermination Unit.

Yaksha
Weapons from the Yaksha series and below are considered Enchanted Gear.

Myo-o
A Myo-o demon inhabiting an ax possesses a trespassing student named Yūji in the Vampire Reign manga.

Events of 2012
Cursed Gear is something many magical organizations have tried for years to develop for its great power with little success. It wasn't until Mahiru Hīragi, who sought to research the demon curse to save her sister and herself from becoming demons, teamed up with the Thousand Nights, and combined their magic with the Imperial Demon's to successfully produce usable cursed gear. Eventually, they were able to bind and make contracts with demons that are at the level of Black Demons.

Since then Mahiru was hailed as a hero for completing the Cursed Gear.

Once the Order of the Imperial Demons get their hands on cursed gear, they begin to develop hundreds upon hundreds of them for their followers. However, they put restrictions on Cursed Gear to prevent the users from becoming demons right away.

Eventually, the Imperial Demons are confident enough to use their Cursed Gear and destroy the Thousand Nights, but the vampires beat them to it. With this technology, they believe themselves to be the strongest humans.

Trivia

 * Aside from their possession or manifestation abilities, Cursed Gear can also be summoned from across the room directly to its contractor's hands. Mahiru was able to summon Asuramaru to her hand like a manifestation type demon in Catastrophe books 3 and 5.
 * Mahiru, Byakkomaru, and Asuramaru were able to manifest outside and away from their weapons, but only their hosts can see them.
 * Noya Hienma can be seen by anyone as if he is physically manifested, which unlike all demons who only their hosts are able to see them, and interact normally in the real world if released from his blade.
 * Noya can even summon blades as long as he is released from his Cursed Gear, to aid him in battle.
 * When Kureto was possessed by Shikama Dōji, he is able to move his shadow and manifest of his on will to the point of leaving his body as well.
 * Asuramaru and Shikama Dōji are the only two demons who have been used two times.
 * Asuramaru was used by Mahiru Hīragi prior to her death and later became Yūichirō Hyakuya Cursed Gear.
 * Shikama Dōji was used by Mahiru and later passed it down to her younger sister Shinoa Hīragi.
 * Because Cursed Gear wielders are already infected with the demon's curse, other viruses and bacteria can't take hold. Their bodies just return to their ideal state.