What It Means To Be Strong
After hearing that Kirito had killed people in SAO, Sinon asks him how he was able to overcome the memories of the people he killed, but Kirito reveals that he didn't overcome them, instead accepting the weight of them, since it was all he could do to atone for his actions. Then, while thinking about how Death Gun was able to stop the heart of players by shooting them in the game, Kirito realizes that Death Gun did not shoot him with the pistol, but with the sniper instead. Based on this, Kirito deduces that Death Gun had to make preparations in real life to be able to kill the players with his pistol, and that he could've seen players putting their real-life details in the General Governor's Office since it was an open space and the terminals did not offer much privacy. Kirito then brings up the idea that Death Gun could have used his mantle to spy on other players without being noticed. After some thinking, Kirito realizes that Death Gun was actually two people: one shoots the player in-game, the other kills the player in real life by injecting them with a lethal drug. Meanwhile, Kikuoka Seijiro logs onto ALO as Chrysheight under Asuna's request and, after Yui reveals all the information on the incident that she had gathered, Chrysheight explains the situation to Asuna and the others. Asuna then requests Kazuto's whereabouts and decides to go to him in real life. Back in GGO, Kirito and Sinon decide on a course of action and are surprised to find out that they were being filmed by one of the cameras.
Aired 13/09/2014EP 11 - What It Means To Be Strong

Sword Art Online II
One year after the SAO incident, Kirito is approached by Seijiro Kikuoka from Japan's Ministry of Internal Affairs and Communications Department "VR Division" with a rather peculiar request.
That was an investigation on the "Death Gun" incident that occurred in the gun and steel filled VRMMO called Gun Gale Online (GGO). "Players who are shot by a mysterious avatar with a jet black gun lose their lives even in the real world..." Failing to turn down Kikuoka's bizarre request, Kirito logs in to GGO even though he is not completely convinced that the virtual world could physically affect the real world.
Kirito wanders in an unfamiliar world in order to gain any clues about the "Death Gun." Then, a female sniper named Sinon who owns a gigantic "Hecate II" rifle extends Kirito a helping hand. With Sinon's help, Kirito decides to enter the "Bullet of Bullets," a large tournament to choose the most powerful gunner within the realm of GGO, in hopes to become the target of the "Death Gun" and make direct contact with the mysterious avatar.
(Source: Crunchyroll)