Sword Art Online Light Novel Volume 04
After thwarting the would-be ambush, Kirito and Lyfa set out for Aarun, towards the world tree, only to be sidetracked by an event and end up in the Underworld, «Jötunheimr». With some help from an unlikely ally, they reach the city only to find that the way to the world tree is locked.
Looking high above you see the land and then the sky from the underworld «Jötunheimr»; introducing the undergrounds of the fairy world, a dark world of ice and snow, dominated by dreadful evil-God-class monsters.
Chapters of Sword Art Online Volume 4
After falling for the illusionary trap of a monster mimicking a town, Sylph warrior Lyfa; the game persona of Suguha; and the Spriggan race Kirito have trespassed into the underground world: «Jötunheimr». While hiding in a shrine, they witness a battle between two evil-Gods; a three face humanoid shape giant against an elephant-headed jellyfish giant. Feeling sympatric for the giant jellyfish, they provide support and provoke the human giant into following them into a trap, allowing the giant jellyfish to finish it off when both the giants fell into the icy water. Appreciating their help, the giant jellyfish, who they later call Tonkii, became their companion and vessel to travel the icy land of «Jötunheimr».
After avoiding the other evil-Gods, Tonkii took a rest when they reach the roots of the World Tree. As Suguha and Kirito were sightseeing, they were interrupted by the presence by an evil-god hunting party of 24 elite Undine players. As their friend: Tonkii was in trouble, Suguha and Kirito intervene to protect him. During the conflict, Tonkii evolves and suddenly sprout his wings to fly, he soon rain down monstrous attacks and fight off the elite Undine players to near annihilation.
Ready to continue the journey, Suguha and Kirito once again rode on Tonkii, and along their way, they discover the sealed whereabouts of the strongest legendary sword: «Holy Sword Excaliber». Decided to try to capture it in another time, Tonkii finally brought them back upper land, and flew off to meet again at another time. Suguha and Kirito finally reach the beautiful, majestic city known as «Aarun». After the long eventful night, they finally can log out of the game to rest.
After the long tedious task of secretly memorizing the long digit passcode, Asuna unlocks the door and attempt her escape from her imprisonment from Oberon (Aka Sugou Nobuyuki). Exiting from the golden cage, she finds herself in a secret laboratory where Sugou and his subordinates perform their illegal experiments with the trapped mind of the human players from the «SAO» incident.
Despite being carefully quiet to not get notice, she was caught right before she can escape through the exit in front of her. Despite her struggle, she was soon brought back to the golden cage and is now more secure than before; however she was able to steal a silver key card from one of the subordinates. As the passcode have been change, she patiently rests until another opportunity arises.
Back at the real world, Kirito and Suguha spend the morning improving their sibling relationship. Later, they both travel to the medical institute to meet the sleeping Asuna; as Suguha watch her cousin Kazuto, she finally knew how she felt about him. After returning home, Suguha activate her Amusphere and resume her online life as the Sylph warrior: Lyfa.
Finding herself at the inn of the Alfheim’s capital city «Aarun», she met with the Spriggan Kirito and made their way to the World Tree. When they arrive, Yui told Kirito that she felt Asuna’s presence, and they fly to try to meet her in their excitement. As the system would not allow them to pass a certain point in the air, they were force back. However Asuna felt the voice of her daughter and toss them the silver key card she stole from one of her imprisoners. After obtaining the key card, Kirito part ways with Suguha and left with Yui to the gate that leads into the World Tree.
Accepting the challenge of the guardians who protects the passage, Kirito fight his way towards the goal. The odds were against Kirito; he was defeated and left in his End Frame, however he was soon revived and rescued by Suguha. Ignoring Suguha’s warnings, Kirito was still persistent in continuing the impossible challenge, and he suddenly spoke Asuna’s name. Leading to the discovery of each other identities; the Spriggan Kirito as Kirigaya Kazuto and the Slyph warrior Lyfa as Kirigaya Suguha.
After learning the truth, Suguha was in heartache. She log out of the game and isolate herself in her room. When her cousin Kazuto tries to confront her, she finally told him everything about how she felt about him; afterwards she closes the door between them and sat by herself. After contemplating for a period of time, Kirito left Suguha a message that he will be waiting for her in ALfheim.
Suguha returns to ALfheim and while considering whether to meet her cousin, she met her old companion Recon, the game persona of her classmate Nagata. He helps Suguha made up her mind and with his help, she left to meet Kirito. Upon their meeting, Suguha asks Kirito to another duel, which ended in a tie as both drops their weapon at the last final moment. In the end, Kirito apologises to Suguha for the pain he had caused her.
With the assistance of Suguha and Recon, Kirito re-challenge the guardians; during the difficult battle, Recon performs a self-sacrifice move. They were later supported by the Sylph Lord, Sakuya, the Cait Siths lord, Alicia Rue, the Dragon Knights and a large player group of ancient weapon class. With their help, Kirito was able to make it to the goal. Still followed by the guardian knights, Kirito quickly uses the silver cardkey he obtained from Asuna. While holding onto Yui, they both teleports into the gate. After they landed, Yui returns to her state as a 10 year old girl, Kirito follows Yui’s directions to the golden cage, and they finally reunite with Asuna.
Sugou interrupts the couple’s meeting, and uses his power to immobilise Kirito and Asuna, however Yui was able to escape. After Sugou pins Kirito to the ground with his sword and alters his pain receptors, he began tormenting Asuna. When the situation was looking grave, Kirito receives an unexpected help by the voice of Kayaba Akihiko. After removing his sword that had restrained him, he accesses the system and under the ID of Heathcliff, he gains the controls as the system administrator and seal Sugou from using his power. Wielding his black sword, he challenges Sugou to the match; which Kirito won and inflicted great pain onto Sugou; slowly hacking him into pieces until he disappears. Afterwards Kirito finally freed Asuna from the game, and then spoke with the ghost of Kayaba. Kirito was then given the program: the «World Seed» before he left.
Kirito met Suguha in his room when he returns back at the real world and gave her his sincere gratitude. He quickly left on his bike into the snowy night and was on his way to meet Asuna; however he soon encounters Sugou with a knife. Using the experiences he acquires from the game, he defeats Sugou and restrains him at the parking lot. After entering the medical institute, Kirito told the receptionists about Sugou’s whereabouts. Afterwards, Kirito took one of the guest pass cards and finally reunited with Asuna.
Kirito and Asuna are back together, and are having lunch outside of their school. Both attended the special school made for the student players from the «SAO» event. However, the Player killing «Orange Players» are being treated in counselling and are under observation. Kirito and Asuna talk about the following events, about Asuna’s father, Sugou’s sentence, the future of VRMMO, and also about Kayaba Akihiko whose death became clear to the public at March 2025. Kirito had met with the female graduate student who helped Kayaba: Koujiro Rinko, and learn about Kayaba’s aims; scanning his brain and storing his memories and thoughts as digital codes into the network.
Watching the couple from afar; Lisbeth, who real name is Shinozaki Rika, and Silica, who is Ayano Keiko, were sitting near the windows on the west side of the cafeteria. Once Kirito had told Lisbeth about the «ALO incident» and what happened to Asuna, she and Silica formed the alliance with a «One Month Truce» to allow Kirito and Asuna to spend time together, which Lisbeth is now regretting.
Along with Asuna and Suguha, Kirito attended the party at the «Dicey Cafe», which have been reserved for the off-line meeting of the «Aincrad Capture Commemorative Party»; planned by Kirito, Lisbeth and Agil. Watching the occupied table of Asuna, Lisbeth, Silica, Sasha, Yuriel, Suguha and the other female players; Kirito met up with Klein, and Sinker is now married to Yuriel.
With the help of Kayaba’s female assistant: Rinko, as well as Yui and Agil. Kirito uploaded the «World Seed» program; allowing anyone with a sufficient server to download the free package, and design a new VR game world in their preference. In addition, «The Seed» program can also be used for education, communication, tourism, and so on.
Afterwards, there was a seconding party in ALfheim; the game «ALfheim Online» was still operating and was now funded by a new company. Deciding that the role of the «SAO» Kirito was finished, Kirito started a fresh new version of the «Spriggan» Kirito. To Suguha’s surprise when her cousin have led her to the meeting place of all their friends, there was a new addition to the game; the rebirth of the floating castle «Aincrad».
Source: This page is a work from swordartonline.wikia.com and I dont claim ownership of this post, visit this site if you want to know more about SAO.