Tomori Kusunoki is returning as the main lead Llenn. Other returning cast members include Yōko Hikasa as Pitohui, Chinatsu Akasaki as Fukaziroh, and Kazuyuki Okitsu as M.
Masayuki Sakoi (Cautious Hero: The Hero Is Overpowered but Overly Cautious, Matoi the Sacred Slayer, Princess Resurrection) is returning to direct the anime at A-1 Pictures (Studio 3Hz transferred its animation planning and production business to A-1 Pictures in June). Yōsuke Kuroda (My Hero Academia, Trigun, Gundam Build Fighters, Mobile Suit Gundam 00) is returning to oversee the series scripts, and Yoshio Kosakai (The Marginal Service, Needless) is returning as the character designer and chief animation director.
The story follows Karen Kohiruimaki, a 183-centimeter-tall (6-foot-tall) college student who's insecure her height, and is bad at dealing with people in the real world. She enters the world of Gun Gale Online with her avatar, Llenn, who is less than 150 centimeters (5 feet) tall and wears all pink. She meets a beautiful, brown-skinned female player who goes by Pitohui. They hit it off, but one day Pitohui pressures her to participate in "Squad Jam," a team Battle Royale variation of the Bullet of Bullets tournament.
The anime adapts Keiichi Sigsawa's Sword Art Online Alternative: Gun Gale Online light novel series, which is itself a spinoff of Reki Kawahara's Sword Art Online light novel series. The first Sword Art Online Alternative: Gun Gale Online anime premiered in April 2018 and ran for 13 episodes. Aniplex of America streamed the series as it aired on Crunchyroll and Hulu, and also released the series on Blu-ray Disc in 2019.
Yen Press is releasing Sigsawa's light novel series in English.
Sources: Aniplex x Kadokawa Anime Matsuri livestream, Sword Art Online Alternative: Gun Gale Online II anime's X/Twitter account