Chains

Chains, at least a certain type, in Seraph of the End are a modification that a select few individuals have that essentially allows them to wield an abnormally dexterous, and multi-purpose weapon system. Chains can also be used to sap the power of others to supplement one's own strength. Apparently inherent to who is using them, their versatility affords their wielder to retain a connection between severed body parts. Manipulated through some means, the precision and speed at which they can strike allows for a great deal of control in various situations. Upon striking into a human, the chains are capable of breaching a demon's realm and even bind and capture them.

Manga
In the Owari no Seraph manga, and the prequel story Seraph of the End: Guren Ichinose: Catastrophe at Sixteen manga, the light colored metallic appearing chains are consistently similar regardless of who is using them. The short-link chains can extend to very long distances. They can curve or bend sharply to reach their targets.

Anime
For the Seraph of the End anime, long dark colored interconnected rods are used. These end in a rhombus shaped spiked tip. They become completely red when draining blood.

Background
From what can be observed the chains are an artificial creation, a relatively modern one based on them not being seen in the ancient past. Saitō of the Hyakuya Sect had his own body modified where the chains could emerge from various points. Tenri Hīragi, the head of the Japanese Imperial Demon Army could also use chains. He described a curse being broken where his body could not heal, indicating the specific magical nature involved. Guren has connections with both military and living being experimenting organizations.

For their spell based properties, more chains can be produced than what would be able to fit within a caster's body, so may be a creation being produced rather than emerging from within. They require no verbal activation, unlike many other weapons. The chains act as both an independent being targeting who the user wants, to an asset that can be used however one thinks.

Capabilities
One chain alone can strike with remarkable exactness, and an incredible amount of speed. Where conventional weapons such as cursed gear and vampire swords at least need to be swung, and often invoked, chains can materialize and strike almost instantaneously with a great amount of force. These can be aimed at selected and often specific points, and there are many of them. The chains can work in conjunction, jabbing all at once, or perform multiple functions as gatherings of them can operate independently. Their strength does not falter depending on the length, and they are capable of holding up many people.

The chains can exit a user's body from the palm of their hand or out from their back, then in convenient areas such as the soles of Saitō's feet to allow him to remain positioned on a ceiling. In the case of severed limbs, a chain will hone in to reach the body parts and hold them together from the opening of the severed tissue. They are strong enough to break through cursed gear manifestations, including the Genbushin shield. In terms of the damage they can sustain, the sheer durability and number of them can collide with Shikama Dōji's scythes. Shot at by the Byakkomaru cursed gear rifle, the chains break in one chain link area. With magic involved, the chains can assume beast like traits where the spiked tips can become snake heads. To a greater extent, these can develop into the upper torso's of what resemble apocalyptic beasts.

Story
At Nagoya airport, when Kureto orders the experiment to begin, a flurry of chains blast outwards into the air, before bending at right angles to stab into the surviving members of the Moon Demon Company. The chains impalement is what causes the deaths of many soldiers including Rika Inoue and Shūsaku Iwasaki. Upon being skewered, bodies were suspended in the air. The chains do not attack newcomers such as Yūichirō Hyakuya and Mikaela Hyakuya unless commanded to. Ordered to do so by Aoi Sangū, the chains were seen to be coming out of a truck. When Guren arrives, with Kureto Hīragi's order, the chains follow his will in wrapping themselves around Guren's sword arm. Directed to drink the blood of the sacrificial humans, of demons, and progenitors, the chains can absorb the blood and send it to the seraph within the truck. The chains reach out of the truck itself, though from what is not shown, and stab into Mirai Kimizuki above whose body is controlled by a seraph. The chains play a part in the Japanese Imperial Demon Army exerting control over Mirai as a seraph with the demon Abaddon they summon.

When Tenri sees Kureto break through his door, he has many chains, spectrally tipped with open fanged snake mouths emerge from his back. Hitting the ground in places when Kureto avoids them, they are able to wind round and pierce the spell tag barrier that Aoi has established where the ends have formed into snake heads. Four chains reach up from Tenri's severed neck and hold his head that was sent into the air. Having reformed Tenri, chains then rush towards Aoi, before vertically slicing off Kureto's right arm, and horizontally cutting off his left leg. After Tenri is struck by Adaddon's blast, he notes his body and the curse supporting it have been broken, where the chains and their outstanding regenerative capabilities play no further part in keeping him alive.

At Shibuya the personnel involved with activating Mirai as a seraph are targeted by chains once Saitō arrives. Seen by Shihō Kimizuki, the chains move out of Saitō's back to place themselves in the ground. With assistance from Basteya Irclu and many other members of the Hyakuya Sect army using spell tags, cracks in the sky can allow chains to pass through and stab all involved. Rendering them unconscious, the chains sap the entire army's strength to increase Saitō's. After a chain is used to bind Shinoa Hīragi's hand, whose body is possessed by Shikama Dōji, one is also allowing Saitō's head to float in the air after it is decapitated. Once this neck chain is severed, many burst out where they hone in to stab into the ground. Travelling outside to scale the walls of a building, in the place of them are the heads of various white eyed creatures. These fire upwards where they explode upon contact with the First's scythes.

With Mahiru-no-Yo's encouragement, Guren Ichinose means to betray everyone and chains are involved with that. Spreading out from his back, the chains can be blown apart by Shinya Hīragi's rifle fire. At Mahiru-no-Yo's command, the chains fire towards Shinya, to be blocked by Mito Jūjō and Norito Goshi. When Noya Hienma has emerged, the chains are used by Guren to sap the power of his squad, including Sayuri Hanayori and Shigure Yukimi. The supplementary power from the chains bolsters Guren as a demon, with Mahiru-no-Yo ever more to the point where he can challenge the First.

After Saitō had endured the effects of a Sinful Key, his upper torso was what remained with chains coming out the bottom. Angled, one could zip past Ferid Bathory's face to scratch it. With Saitō still, the chains could be manipulated to strike at Ferid, then target and seize his arm a distance away. Keeping him bound, the chains were largely still yet rattled slightly as Saitō focused on healing. The chains were still wrapped around Ferid's dismembered arm after it was struck off by Urd Geales, and did not react to Crowley Eusford holding the limb. They are examined by Ky Luc when Saitō's body is stabbed into. By striking into the ground, the chains can lift up Saitō's upper torso.

While Saitō is bound by a physically identical set of chains, his distinct in what they can do chains are seen breaking out the back of his chair within his prison. These stab into vampire nobles around him, and violently spin similar to the air currents of a whirlwind. Simultaneously they yank the vampires around while lifting Saitō into the air. Keeping him suspended, Saitō keeps the chains around him while assailing Lest Karr and Ky Luc with them. Multiple jabs towards them can be evaded, and blocked, where they do not impede Ky Luc's movements after one stabs through his eye. When it transpires that this Saitō fought was a spell tag based illusion, the chains could also be displayed by such an entity.

A great many amount of chains coalesce into a pattern, a pentagram, from out of Saitō's hand. Two individual chains move apart from the formation to stick into Kureto Hīragi and Shinya Hīragi. They are able to locate their demons, Raimeiki and Byakkomaru where they are alone in their respective realms, and once the chains erupt from their chests they proceed to bind them in a thick cocoon of chains. The chain pentagram appears behind Sika Madu in his location. Chains from Kiseki-o's coffins that the structure is a part of are what dive towards the First.

When a chain is sent into Shinya's chest, it can appear from Kimizuki's body who is physically far away. After positioning itself, the chain can allow Saitō's voice to carry over to communicate with Guren. In turn, a single chain breaks out of Guren's hand. In Sika Madu's location, the chains gather themselves and rise into the air. They strike from multiple angles at the First all at once.

In response to Sika Madu calling for Rigr and Urd's help against an attack including seraphs, chains can rapidly seize the First, pull him out of harms way and bring him through Kiseki-o's coffin to safety from the threats there. A chain binding, linked to these magical based ones or not, is used to strap Sika Madu's wrists together to keep him held there.

When Shikama Doji is imprisoned and claims the vampire progenitors have already cut themselves free of his strings, Saito's chains are used to fly through the bars and into the First's neck where they draw his blue blood that spills on the floor. Remaining there, another chain is fired when Saito answers the First he cannot trust him. After spell tags cancel Shikama Doji's telepathic communication, the chain in him thuds to the ground. When Shikama Doji suggests that the vampire sacrifice element to his resurrecting his son plan could be of interest, a multitude of Saito's chains drive into him.