|Spoiler Alert: This article/section contains details about future plotlines described in the light novels, not covered in the anime. Do not proceed unless you want to be spoiled. |
Sachi (サチ, Sachi?) was a supporting character in the Aincrad Arc. She was one of the 10,000 players who were trapped in «Sword Art Online» and a member of the Moonlit Black Cats guild. Along with the majority of her guild, Sachi was killed in the 27th Floor Labyrinth on June 22, 2023, after they ventured into a trap in a secret room inside the Labyrinth.
In the real world, Sachi, along with all the other original members of the Moonlit Black Cats, were in a computer club at their school. She also happened to live fairly close to the leader of the guild, Keita.
Sachi was a petite girl with shoulder-length black hair. She wore a light blue tunic with a chestguard, a knee-length short skirt and grayish boots. In battle, her weapon was a two-handed long spear. Although she temporarily tried out wielding a sword and shield to help Tetsuo tank monsters, she eventually had to switch back to using a spear due to her fear of fighting monsters at close range.
Sachi was a shy and cowardly girl who had harbored great fear of the death game and dying. She even admitted that she never intended to leave the Town of Beginnings and hated going into battles. After Sachi ran away from the guild and Kirito managed to trace her, he assured her that he would not let her die. Ever since then, Sachi became close to Kirito and one day noticed his real level. Although she wondered why he had been hiding his level, she decided not to tell anyone in the guild about it, believing that one day he would tell them the reason personally. After finding out how strong Kirito was, she could finally sleep soundly by his side, feeling safe by his side and happy that she was significant to him.
On April 8, 2023, Sachi, along with the other members of the Moonlit Black Cats guild were having a hard time fighting monsters in a dungeon due to only having one tank. Kirito accidentally came across them and decided to help them safely leave the dungeon, but intentionally limited his abilities to hide his real level. After the guild had been safely escorted out of the dungeon, the guild invited Kirito to a drink as a thanks for saving them. At a tavern, the leader of the guild, Keita, asked Kirito to join their guild and their leader asked Kirito to mentor Sachi into being able to switch to sword and shield from her original profession of a lancer.
For a period of time, Kirito did try to help Sachi with her new position, but she could not handle it due to the closer range to monsters and her fear of battles and one day ran away. Kirito managed to track her down by using Tracking and found her hiding at a drain with an invisibility cloak. Kirito comforted Sachi and told her that he would not let her die. After the incident, Kirito told Keita that Sachi could not continue being a forward and that he himself would fill in this role. From the next night on, Sachi would come to sleep in Kirito's room, as she claimed that she would be able to sleep peacefully if she continued to be with him and hear his calming words.
However, Kirito was not able keep his word. On June 22, 2023; the guild leader went out to buy a home for the guild, the other guild members decided to head to a dungeon to get enough money for a celebration. The group decided to head to a Labyrinth just three floors below the current front line. Although the hunting was proceeding smoothly and the guild managed to acquire enough funds, Ducker found a treasure chest and opened it, triggering a trap which locked down the area, made multiple monsters spawned around the trap, and prevented the use of teleportation crystals. At exactly 5:45:13 PM, Sachi died.
On Christmas morning that year, a time-delayed message left by Sachi opened up in Kirito's inventory. The message told him that she had already known of his higher level and also told him not to blame himself for her death, which she had predicted would happen due to her nature. She requested Kirito to survive in the world of SAO, and to find the reason why such a world was built. Finally, Sachi sung "Rudolph the Red-Nosed Reindeer" and her final goodbyes gave Kirito the strength to live.
On June 22, 2025, at 5:45:13 PM, exactly two years after Sachi's death, her emotions preserved by the Cardinal System temporarily interfered with Asuna's avatar in ALfheim Online. The former vice commander of the Knights of the Blood experienced a vision, in which she witnessed an image of Sachi slowly and lovingly singing "Rudolph the Red-Nosed Reindeer." After finishing the song, the apparition turned to Asuna and requested her to tell Kirito for her that she was happy, before the vision ended.
- See: Sachi/Image Gallery
- In the light novel, Sachi and Kirito had a shared inventory page separate from their individual inventory, which either one could access at anytime, mainly used to put common items such as potions and crystals for their convenience. The creation of this slot was requested by Sachi under the guise of being able to share potions between them, even though the guild inventory could be used for this purpose. The real reason why she wanted this slot was to be able to leave a comforting goodbye message to Kirito, in case she died before Christmas.
- Sachi's death was one of the driving factors for Kirito's refusal to join another guild, and re-embracing the path of a solo player, until over a year later, when he was comforted by Asuna and joined the Knights of the Blood.
- In the Blu-ray/DVD package volume 2, the character song CD featured Sachi (Hayami Saori) singing "Memory Heart Message" as the 2nd Character Song for this series. This CD is bundled along with the 3rd Character Song, which is sung by Silica (Rina Hidaka).
- In the web novel, Sachi was Kirito's first love prior to Asuna. In addition to this, Kirito's and Sachi's relationship was depicted as being more intimate, and close in the web novel version of the story. However, subtle changes in the text of the published version imply that Kirito and Sachi were not as close as in the web novel.
- In Sword Art Online: Infinity Moment, Kirito's inventory contains items from Sachi (and Asuna) separate from other items. The shared inventory contains a message record crystal that can only be activated in Kirito's room.
- In Sword Art Online: Hollow Fragment, an AI version of Sachi is found within the last section of the Hollow Area. However, when she meets Kirito, she appears to have little to no memory of him, or the guild. Unlike the original Sachi, she also appears to be willing to fight, despite being at such a low level.