Sword Art Online: Alicization – War of Underworld finally aired its 12th and final episode. However, it looks like the story of Alicization will continue, as the anime ended teasing the upcoming final battle. And as the anime ended, it also announced that the “Last Season” of Alicization will be happening in April 2020.
From the key visual, it looks like it will really be intense, and the other SAO characters like Leafa and Sinon are finally joining in.
Previously, the light novels’ editor, Kazuma Miki, revealed that the anime will cover the entire Alicization arc. The arc itself lasts for a whopping 11 volumes, from Volume 9, all the way to volume 19. This makes the arc longer than all of SAO’s previous story arcs combined. Expect the staff to reveal more details soon.
source: Sword Art Online official website