World Rejecter Arc

The World Rejecter Arc is a story arc in Shinyaku Toaru Majutsu no Index, covered in Shinyaku Toaru Majutsu no Index Volume 14. The story arc introduces Kamisato Kakeru, a "normal high school boy" who wields a right hand with a mysterious power that's different from Kamijou Touma's, and the consequences of their first formal encounter while dealing with two supernatural creatures that involve Patricia and Leivinia Birdway.

This arc directly follows the events of the Magic God Invasion Arc, occurring on the night after High Priest's rampage on Academy City.

Gremlin
The Magic Gods of the true Gremlin had been living in a Hidden World, a phase separate from the rest of the outside world, and were content to remain that way. However they had concerns about distortions caused by their immense power and existence, which would influence the outside world, even if they didn't intend to. In order to address this, they wished to obtain a "scorer" who would direct them and their power and regulate the distortions, giving them piece of mind in exchange for having their wishes granted. The individual they intended to be their scorer was Kamijou Touma, bearer of the Imagine Breaker, a power born from the wishes of all magicians, with the Magic Gods being the largest influence.

However, the actions of Othinus and her interactions with Touma in November led them to have subconscious doubts regarding their chosen scorer. As Othinus was about to die in Denmark, the High Priest intervened to save her death, as it might have provoked a change in Touma undesirable to Gremlin. Their hidden world was then breached by Aleister Crowley who engaged them in battle, eventually retreating with a third of his body badly burned but obtaining the Magic Gods' base parameters.

Following the loss of their hidden world, Gremlin decided to take action themselves and using a spell devised by Zombie in order to enter the world without risking destroying it, the Magic Gods entered Academy City on December 1st. The incident in the Dianoid with St. Germain delayed them, but as they were about to make a move, they were contacted by Aleister, who swapped out Zombie's spell with his own spell calibrated from the parameters he'd obtained in the previous battle, greatly weakening them. A crucified Zombie was then launched into the Magic Gods' midst by Kihara Noukan.

On December 3rd, the High Priest personally made contact with Touma at his school during the Anti-Crime Orientation and offers him the position of Gremlin's scorer and their power via proxy. Recognizing similar circumstances to the 'happy world' Othinus had subjected him to and not wanting the world to become a twisted puppet show, Touma rejected the High Priest's offer, leading the Magic God to try and change his mind through destruction. Commandeering an acrobike, Touma fled his school to draw the High Priest away, ending up taking Misaka Mikoto with it. The destructive chase through Academy City eventually concluded in School District 23, where the High Priest was launched into space with a silo-type mass driver. He managed to seize control of the Arrowhead Comet and set it on a collision course with the city. However he was killed by Kihara Noukan, using Aleister's willpower channeled through the Anti-Art Attachment, and the comet destroyed in mid-air, the explosion shattering all the glass in Academy City.

After the High Priest's death, Niang-Niang attempted to destroy the city to eliminate the threat to them but was suddenly attacked and exiled by Kamisato Kakeru, a boy with a special right hand, World Rejecter. The other Magic Gods met a similar fate and only Nephthys was able to escape being completely exiled, due to her separated organs. Mailing herself to Touma, Nephthys sought his help, pointing out that Othinus was also going to be in trouble.

World Rejecter
Due to the doubts which arose in the minds of the true Gremlin regarding Kamijou Touma, their subconscious wishes, with the majority of the Magic Side's power behind them, began to form a new power, World Rejecter. Formed from wishes to escape to a new world rather than cling to the current world, the World Rejecter is capable of exiling individuals with conflicting desires to excess regions in the world's timeline, as well as powers and constructs originating from them. The existence of this power wasn't known to the Magic Gods or even Aleister Crowley, though Laura Stuart was aware of it.

The World Rejecter manifested in the right hand of Kamisato Kakeru, an ordinary high school boy who lived an apparently ordinary life in an ordinary town outside of Academy City. Around the start of November, Kakeru and his life began to be affected by a strange influence, eventually leading to World Rejecter's full manifestation two or three days prior to December 3rd, around the time the Magic Gods descended into the world. In the short time in-between, Kakeru was involved in various incidents and saved over a hundred girls, becoming acquainted with the worlds of magic and science.

The rescued girls, including some of Kakeru's former friends and acquaintances, formed the Kamisato Faction around him. Disturbed by their dependence and affection towards him, something he believed shouldn't be directed towards an ordinary high school boy like himself, Kakeru began to believe that they had been changed by the World Rejecter, not believing at all that his own actions drew them to him. Hating that his power had apparently warped the girls into a harem, on finding out about the Magic Gods who had given him the power and believing it was a deliberate action, Kakeru decided to eliminate them in revenge. He also learned of the Imagine Breaker and decided to meet Touma, due to their apparently similar circumstances.

Sample Shoggoth
At some point between late November and early December, Patricia Birdway accompanied an Academy City sponsored research team to Antarctica, part of a study of changes in the ocean currents due to changing ice levels at the poles. While there, they encountered a parasite, later named Sample Shoggoth, which infested Patricia's body, consuming her fat and taking over its functions, putting her life at risk. Visiting different medical institutions for a way to deal with the parasite, Patricia eventually ended up in Academy City. The parasite was not a natural lifeform, speculated later by Kamisato Kakeru to be comprised of discolored Dark Matter and used in order to set a trap for him, due to his tendency for saving girls.

Around the same time, Leivinia Birdway desperately searched for a way to save her sister. Unable to find a solution with her cabal's methods, Leivinia left the Dawn-Colored Sunlight in order to find a way to cure Patricia's condition by herself. She eventually developed a hybrid method based on cannibalization and other elements from Africa, intending to have Patricia consume an organ she was growing inside her to replace the fat she'd lost and drive the parasite out. However due to Patricia's lack of knowledge concerning magic, Leivinia's reluctance to explain and the repercussions of a new organ being grown within the human body, she rejected the method out of fear for her sister's life and tried to stop her from going through with it.