Sword Art Online: Lost Song

Lost Song takes place in Svart ALfheim, a set of floating continents in ALfheim Online. Two of the continents are "Flosshilde", an ice-based region,[17] and "Woglinde", a grassy area with windmills.[18]

Based in the same continuity as Hollow Fragment, the game follows an alternate timeline from the original series; instead of escaping Sword Art Online on floor 75 like in canon, the players were forced to progress through the game's remaining 25 floors. Lost Song occurs at the same chronological point as the Gun Gale Online arc in Sword Art Online II, but the characters are instead exploring ALfheim Online, the newest virtual reality MMORPG to be released.[19] Lost Song introduces three new characters that play a role in the plot: Nanairo "Seven" Arshavin,[9] an idol and Russian scientist studying virtual reality; Nijika "Rain" Karatachi, an SAO survivor[20] and Seven's older sister[21] who follows Kirito during the story;[22] and Sumeragi, Seven's bodyguard.[23] Seven and Sumeragi are leaders of a guild called Shamrock, Seven being the head. While Seven is at a lower level, her guild mates are among the strongest players in ALO, with 30 percent of the top 100 players being Shamrock members.[24] Sumeragi is the top swordsman in ALO, having defeated Eugene, the general of the Salamander race, in battle.[25] Rain is a former member of the guild, being expelled after lying to other guild members, followed by capitalizing on the time between her removal and the official de-registration of her guild status to steal information.[26]

After the events of Hollow Fragment and escaping Sword Art Online, Kirito expresses an interest in playing ALO, and decides to join after hearing of Seven's work in the game.[27] Rain, aware of Kirito's feats in SAO, decides to follow him, though he notices her presence. The two eventually meet when she was attacked by a field monster in a valley, and Kirito invites her to join his adventures.[28]

Kirito begins to express doubts about Shamrock and Seven's fan club, and decides to attend one of her concerts.[29] There, he notices that the attendees become motivated to perform Seven's interests that she mentions onstage.[30] Seven later reveals that Sumeragi is her research partner for a project she is working on,[31] known as the Cloud Brain. She describes the experiment as a network that unites ALO players' emotions into one, as seen at the concert.[32] She invites Kirito to assist her in creating it, but he turns it down, as he wants to enjoy playing the game with his friends.[33]

Returning to the final dungeon, Kirito notices Sumeragi, who challenges him to a duel. After being teleported to a different area, the two begin fighting.[34] With the usage of Skill Connect, a game exploit in which two consecutive Sword Skills are used without delay, Kirito defeats Sumeragi.[35] Kirito advances through the dungeon to confront Seven, while Sumeragi and other Shamrock members transfer their Original Sword Skills (OSS) to her.[36]

Upon reaching the boss room, Kirito finds out that Seven had already defeated it by herself.[36] While she discusses the results of the project, Rain questions her actions and how they interfere with her idol status.[37] The three begin fighting, and despite possessing a wide array of OSS, Seven is defeated.[38] An angered Seven proclaims that she will be the one who clears Svart ALfheim and her avatar corrupts as a result of overload from the OSS.[39] As the battle continues, Rain tells Seven that she does not want to fight,[40] and after Seven's loss, Rain consoles her while her HP decreases to zero.[21]

Afterwards, Seven stops performing concerts ingame, as Shamrock membership declines.[41] After logging out, Kirito meets Rain and learns of the rift between her and Seven that prompted her to play ALO.[20] Back in ALO, Seven meets Rain again; Rain tells her about their childhood and their split after their parents divorced. After she was reminded of two Russian greetings that Rain had taught her, Seven's memories return and the two are finally reunited.[42]

As a supplement, Re: Hollow Fragment, an improved version of Hollow Fragment, was bundled with Lost Song as Sword Art Online: Game Director's Edition and released in Japan on November 19.[47] Re: Hollow Fragment was also available as a free downloadable if players pre-ordered Lost Song.[48] At Dengeki Game Festival 2015, it was announced that Lost Song and God Eater 2, also published by Bandai Namco Games, would have DLC from the other game: on April 9, Dengeki PlayStation magazine released a serial code of Kirito and Sinon's costumes for God Eater 2, and 14 days later, released a code of GE2 characters Julius and Alisa's costumes for Lost Song.[49] At Tokyo Game Show 2015, Kuroyukihime, from Sword Art Online author Reki Kawahara's series Accel World, was added as another playable character in Lost Song.[50]

Lost Song was released in Japan for the PS3 and Vita on March 26, 2015,[51] while a Traditional Chinese version was released on April 28.[52] An English-subtitled version of the game was released in Asia on May 12,[7] the PAL regions on November 13,[53] and North America on November 17.[54]

Within the first week of its release in Japan, the PS3 and Vita versions sold 55,090 and 139,298 copies, respectively, with a total of 194,388 copies being sold. The two versions' sales were the sixth- and second-most of the week, respectively.[60] The numbers reached as high as 65,000 (PS3), 177,000 (Vita), and 18,000 (PS4). In a January 2016 interview, producer Yousuke Futami stated the game had sold 100,000 copies in North America—30,000 of which were downloaded—and 50,000 in Europe.[61]