Sinon's Traumatic Past

Shino Asada, or Sinon, suffers from PTSD due to a traumatic event from her childhood. At age 11, while at a post office with her mother, a man attempted to commit a robbery. He pushed Sinon's mother to the ground and held the workers at gunpoint, but Sinon managed to bite his arm and cause him to drop the weapon. She picked up the gun and was forced to fire it three times at the man, leading to his death. Although winning the 3rd Bullet of Bullets competition in Gun Gale Online (GGO) gave her greater confidence as she worked together with Kirito, the memory of that fateful day at the post office will never leave her.

As Sinon tried to overcome her phobia of guns and panic attacks at the sight of them, she faced resistance from her former friend and two other girls at her school. They constantly tried mugging her and pointing their hands like guns to take advantage of her panic. In the end, however, she was able to wield a real gun used by the girls to threaten her. 

When Sinon met Kirito in GGO, everything changed. Death Gun, an SAO survivor, had been working alongside his younger brother, Sinon's best friend, to kill players in the game while simultaneously poisoning them to their deaths in real life. When Sinon first faced Death Gun as he held the same gun of her fated past, she no longer felt like the strong and courageous sniper of GGO. She felt like her real self again, terrified to even look at a gun. She thought that by winning the Bullet of Bullets in GGO, she would be able to overcome this fear. In the tournament, when Death Gun stood before her, she lost this drive. She and Kirito manage to get away and plan out how to defeat Death Gun, and they managed to crack the whole case. It took a lot of willpower and determination to beat Death Gun, but they succeeded. They ended up taking on his brother in the real world as well, but Sinon had managed to find strength within herself to slowly begin recovering from her trauma.

Kirito is very important to Sinon because he helped her find courage within herself. They both shared painful pasts, but Kirito explained that closure was what Sinon needed to find. Even while he was suffering from the re-emerging memories of the Laughing Coffin players he killed in SAO, he decided to keep fighting. Sinon found inspiration in Kirito's strong spirit, and she saw him overcoming his own past. She wanted the same for her life, and from then on she was able to start moving forward. The shared pain and bond between Sinon and Kirito allowed them to grow close.