Moonlit Black Cats

Black Cats of the Full Moon (月夜の黒猫団) was a mid-level guild in «Sword Art Online».

Background
Black Cats of the Full Moon was a mid-level guild with relatively few members, although all of them, except for Kirito, knew each other offline as the guild was formed from the members of a school's computer club.

Red-nosed Reindeer
On April 8, 2023, Kirito assisted the Black Cats of the Full Moon and they were celebrating for him. Keita, the leader of the guild, asked Kirito about his level, who lied about it and claimed to be just about as strong as the guild, and then sent him an invitation to join them. Kirito accepted the invitation, but only remained as a temporary member until the guild was strong enough to be independent.

A few months passed by and Kirito assisted the guild, especially Sachi, who was deeply afraid of death. During the time lapse, the members of the guild had hopes of being strong enough to catch up and join the Clearers on the front lines, and with Kirito joining them, they believed they stood a chance of catching up.

On June 22, 2023, the guild finally had enough money to purchase a home, and Keita left to the Starting City to bargain out for one. The other members then wanted to impress Keita by obtaining items from monsters stronger than them. However, while exploring the Labyrinth of the 27th Floor, the guild accidentally triggered a trap in an Anti-Crystal Area, filled with continuously re-spawning monsters higher than their level. The Black Cats of the Full Moon were quickly overwhelmed and all of them were slaughtered except for Kirito who somehow survived but was left distraught. After Kirito informed Keita of the demise of his fellow guild mates, he cursed Kirito's status as a Beater before Keita committed suicide by jumping off the edge of an Aincrad floor.

After the death of his guild mates, Kirito treated a tree growing next to the inn that the guild used as a headquarters as a replacement for a grave for the deceased guild and visited the site every now and then.

Months later, on Christmas Eve, Kirito learned of a revival item called the Divine Stone of Returning Soul that was dropped by the event boss Nicholas The Renegade and sought to search for it in hopes to revive his lover in the guild, Sachi, but was distraught that the item could only revive someone within their ten second end-phase, and not someone months ago. Fortunately, just hours later, a time-triggered recording crystal appeared in Kirito's shared inventory with Sachi just as he was about to leave on a suicide run against a Floor Boos. The message Sachi sent told him that she did not blame Kirito for her death, as she believed that her own character would have led to it eventually, thus persuading Kirito to live on.

October, 2024
On October 9, 2024, Kirito was reminded of the deaths of the Black Cats of the Full Moon when The Army engaged the 74th Floor Boss, The Gleam Eyes, as The Army was unable to use their crystals and were slowly being killed off.

The next day, Kirito was forced into joining the Knights of the Blood guild after losing a duel against Heathcliff. After joining the guild and being asked by Asuna why he had avoided guilds so much even though he was a nice person, Kirito told Asuna about the demise of his former guild, also telling her that he believed that their deaths was his fault and they would still be alive if he had never joined them, thus Asuna comforted him.

November, 2024
On November 7, 2024, after Kirito deduced Heathcliff's true identity as Kayaba Akihiko and was offered to duel him in which Kayaba would free all the players trapped in SAO, the flashback of the deaths of the Black Cats of the Full Moon occurred again in Kirito's mind, who did not want more people to die.