The 25th Floor (第25層,Dai 25-sō?) of Aincrad was a floor that was exceedingly more difficult than the 24th Floor, possessing abnormally strong monsters, complex topography and was thus the site of many deaths in Sword Art Online.
The Clearers reached this floor in February, 2023. As the floor was exceedingly dangerous when compared to the previous floor, it led to death of many players even while navigating towards the next town due to the amount of traps and powerful monsters throughout the floor. By the time the Clearers reached the Labyrinth, they were already at the end of their rope, with only Kibaou’s motivation allowing them to get back on their feet. However, just before the boss battle at the top of the Labyrinth, Kibaou was misled by false information spread and charged at the boss with only around 40 of his guildmates that couldn’t even make up an entire raid party. By the time the main force reached the boss room, over half of the members of the Aincrad Liberation Corps had died and even the reinforcements suffered heavy casualties. Even with the many casualties, the boss was finally defeated, however, none of the clearers were enjoying the feat of reaching the quarter point in their quest. After the battle, Kibaou and his remaining guildmates left the front lines and arrived on the 1st Floor, where they merged with the mutual-aid organization «MMO Today» led by Thinker and formed a congregation which later became known as the "Aincrad Liberation Force" while the Clearers were reduced to 2/3 of their size before the floor was reached due to the casualties experienced on the floor.