Gungnir

Gungnir (主神の槍 (グングニル) ) is the legendary weapon of Odin in Norse mythology. In the world of Toaru Majutsu no Index it is the spiritual item desired by the Magic God Othinus in order for her her to remake the world. Many magic side events surrounding the first half of Shinyaku Toaru Majutsu no Index is related in some way in acquiring a requirement in its construction. Othinus later indeed acquires the spear, and uses it to destroy the world before the eyes of Kamijou Touma.

Etymology
Gungnir in Old Norse means "swaying one", probably to signify how spears are usually wielded. It is usually represented by the Gar rune.

The kanji used for Gungnir (主神の槍), can be translated as Lance of the All-Father, with All-Father (Alfaðir), one of the titles attributed to Odin.

Concept and Origin
Gungnir, as stated, is Odin's spear in Norse mythology. In the Prose Edda was fashioned by Dvergrs but was later obtained by Loki and given to Odin as reparation for cutting Sif's hair. From that point on, It would later be used by Odin in Ragnarok against Fenrir.

The Gungnir is described as having the ability to always pierce clearly through its target and as never stopping during its thrust.

Appearance
Only the replica of the spear has been seen, from the Toaru Majutsu no Index SS: Norse Mythology. There, it looked like a large 3 meter ash tree branch, with many pieces of steel that intertwined around it, and have the characteristics of several other weapons other than the spear, such as the sword and of the ax. It's appearance deceives the eye, a kind of Trompe-l'œil. It pulsates like a living being, like a snake wrapped around a tree branch.

However, in Shinyaku Toaru Majutsu no Index Light Novel Volume 8, the spear that Othinus wielded after taking the spear from out of her eye was different. Here, it was a golden spear with a ribbon-like design intertwining with each other at the end of the handle and below the blade. The tip of the lance was not a sharply pointed blade like on a knife. It was a wide blade as if a double-edged sword had been forcibly attached. It's broad blade also have design that somewhat looks like a branch with leaves on it.

The Gungnir that was wielded by Othinus is most likely 3 meters as well, on the basis that the lance produced through its long complicated ritual and the one that Othinus took from her eye is the same. Later, when Leivinia Birdway's Gungnir appears, it is much smaller and only slightly towers over her. The ribbon-like designs also turn leaf-like in shape. It is still made out of gold and had a tree-like design.

GREMLIN's ritual for the creation of Gungnir
After gathering all the requirements for its creation, GREMLIN prepared them for their ritual. They used the massive volcanic energy at Hawaii as a reactor core and then stored it inside Mjölnir. Although failing in capturing Fräulein Kreutune to turn her into a Holistic esper, they instead acquired the organs of Kakine Teitoku to produce Dark Matter and remake into holistic esper for them as a substitute for Fräulein. They later had Bersi construct a large scale and high-speed parallel processor for them, allowing for the ritual to switch to either magic or holistic esper when the other is not enough to construct it. Bersi later hooks up the organs with the parallel processor, which sends out the proper signals in to make the organs spit out Dark Matter in the form they want.

During the part when the organs were forced to produce Dark Matter, Kakine Teitoku regains consciousness and take form using Dark Matter. He tries to rebel and nearly swallowed up the entirety of Sargasso, GREMLIN's base, using Dark Matter but is cowed by Othinus through force, and is later turned into the shape the size of a volleyball. The Dark Matter later produces a holistic esper, its form was a beautiful white girl surrounded by flower petal-loke things spread out in eight directions. However, it was simply a device that had a form of a human for it was mindless, a hollow doll created to aid in the construction of Gungnir. The production now passes to Marian Slingeneyer the Dvergr for the production of the lance.

They later went to a pool filled with boiling liquid gold that had been turned into a thick transparent liquid. This is because gold was both a symbol of wealth and the material used for the weapons of the gods in Norse mythology, and GREMLIN concentrated all of their techniques into extracting the weapon material side of its meaning. The power needed to ignite and melt all of this and keep it boiling was taken from Mjölnir, who had taken in and controlled the volcanic energy they took from Hawaii. With that the creation of Gungnir begins, and they need only watch the process, interefering only if a manual recovery is needed. This means when the automatic magic ritual stalls somewhere, they need to manually have the the holistic esper accurately continue ceremony with the proper timing in magic's stead.

Slowly, the lance, starting from the handle, bubbles up from the pool of gold. As expected, a problem arose during the process, and they were forced to make use of the holistic esper, which was connected to cables that sent signals out to have it produce high-pitch screams. For some reason, the Dark Matter-made holistic esper began to decompose, which was reason enough for Othinus to interfere, forcing it to keep on screaming. Afterwards, the ritual switched back to the use of magic, though apparently it did not need the use of the holistic esper to fill in what it lacked anymore. Presumably, the lance would've been eventually completed through this method.

Abilities
It is Odin’s spear in Norse mythology. The weapon of the gods signifies in Norse mythology the power of that god itself. The gods could wield their power because they possessed their weapons. There were stories of gods temporarily losing their powers due to losing their weapon or having it stolen. Meaning someone wielding Gungnir wields the power of Odin and could draw out the spear’s true power and would be able to freely use the great power that made Odin a god.

As a weapon of one of the chief gods of Norse Mythology, it is extremely powerful. The replica alone, even with only 70% of its power was enough to overwhelm Kaori. Simply existing, the spear threatened the balance between the magic and the science side.

The spear is said to be able to destroy the legendary weapon Balmung, and any other weapon. It is said to be able to hit any target when thrown, said to be unblockable, and would return to Odin once thrown. However, Brunhild, stated that is something added only by people in legends, and it's true power is that to control the weather and other natural occurences. At that point Brunhild showed Kaori, the power of her Gungnir replica, controlling thunder, magma, water and even salt to damage their battleground, however, it may have been due to the corruption of it by Christian elements.

Gungnir is one of the ways Othinus can bypass her 50/50 restriction. Wielding the spiritual item itself allows her to destroy the world.

Leivinia Birdway's Gungnir
Using the knowledge of Index's 103,000 grimoires, she and Leivinia Birdway were able to construct a lance on their own fine-tuned for human use, which twisted its properties a bit. As such it was a fake as it did not give Leivinia the power to control the power of a magic god nor recreate the world. Referred by Leivinia as an imitation divine technique (無重力生体影響実験室), the lance is only capable of recreating the high-quality phenomenon that was included in the lance - specifically using it as a throwing lance.

To recreate the phenomenon the lance had, Leivinia needed to draw out information of the phenomenon from those who know it, like Othinus. As such, she had to continually receive the knowledge of 103,000 grimoires through Index's singing, despite the danger of the grimoires poisoning her mind. Interrupting the singing however would immediately destroy the lance in an explosion.

If it successfully imitated the phenomenon of throwing lance, it would likely destroy the world.

Toaru Majutsu no Index: Norse Mythology
A prologue of sorts, it is first mentioned by Brunhild Eiktobel in "Toaru Majutsu no Index: Norse Mythology" as her goal of creating a Gungnir by using a replica of it to carve the final rune into the core of the planet giving her the power to save Ceillier Flatley, who attempted to committed suicide because of all the guilt he felt after failing to save her from being repeatedly tortured. When wielding the replica she was only able to draw out 70% of it's full power due to the lacking of the finale rune, yet was still able to create natural disasters like Lightning, Tornados, Volcanic Eruptions, Floods, Earthquakes with ease. Due to her being a Saint as well as a Valkyrie she would at times subconsciously start creating the magical symbols for the Christian Lance of Longinus are mixed in, this would lead to her defeat by Kanzaki Kaori, using the symbolism of the Christian cross against a Saint like Brunhild, which was a weakness to them.

Hawaii Invasion Arc
It is next mentioned in the epilogue of the 3rd Shinyaku Toaru Majutsu no Index Light Novel, after the failed invasion of Hawaii by Marian Slingeneyer, a Dvergr of GREMLIN to another member called Odin (One-Eyed Othinus) were they were planing to use Brunhild Eiktobel to attain Gungnir for their plans.

Lance of Gungnir Arc
GREMLIN started its production after preparing everything and creating a hollistic esper out of the Dark Matter produced by Kakine Teitoku. Once that everything were in place, the production started. The process is essentially a magic ceremony but cannot be completed solely with magic since the automatic work will stall somewhere. To accurately throw in the holistic esper and continue the ceremony with the proper timing, it needs to be switched over manually The ritual is later interrupted by Ollerus who has taken the form of Thor, and causes Mjölnir to explode and most likely knocking out Marian Slingeneyer.

The Gungnir is one of the ways for Othinus to unify the infinite possibilites of her power, the 50/50 restriction that prevents her fully using her powers as a Magic God. She later reveals that she doesn't exclusively need the Gungnir to get rid of the restriction, as there are other ways, like failing 100% to become a magic god, allowing her to unify the possibilities. She reveals that she can make the lance if she wanted to but just wanted to play it safe as her enemies will surely appear to stop her. Now a perfect Magic God made without the lance's help, she then pulled it out from her eye socket in which Kamijou was dumbfounded. She then raised its tip to the heavens and declared that she will just end the world.

Later, during the manhunt for Othinus and Kamijou Touma, Leivinia and Index joined forces to construct their own lance, under the rationale that only a phenomenon extracted from a magic god can kill a magic god. They later appear in a bridge on the city Fredericia when Othinus and Touma tried to cross it to get to the island of Funen. Leivinia shows the lance to Othinus and Touma and tires to use it as a throwing lance, imitating the phenomenon that happens when Othinus used the lance in that manner, extracting it from their mind through Index's singing and sending knowledge to Leivinia. Knowing full well that using the lance in that manner destroys the world, Touma hurries to stop Index's singing. He is successful in doing so, destroying the lance in the process and knocking Leivinia out for a while.