The official Guinaifen reveal was posted by HoYoverse on the official Honkai Star Rail social media, revealing her as a playable character. She's featured in the Light Cone “Subscribe For More!” that has been in the game since its release.

Honkai Star Rail – Guinaifen Reveal

“Would you like to see me break that stone slab with my chest?”

“An outworlder who ended up residing on the Xianzhou by accident. She is now a passionate and vivacious street performer.

With her real name being Guinevere, Guinaifen is the Xianzhou name given to her by her good friend Sushang.

Faced with a whole new life on the Loufu and relying on her adoration of Xianzhou culture, Guinaifen quickly learned skills that would keep her clothed and fed — these being eating noodles upside down, smashing large stone upon the chest of others, and catching projectiles with her bare hands, et cetera.”

Guinaifen is a 4-star Fire character from the Path of Nihility. Judging by the timing of the announcement, she will be playable in Honkai Star Rail Version 1.4 and will debut in either Jingliu's or Topaz's banner.

She's voiced by Morgan Lauré on the English voiceover. For the Japanese voiceover, Hina Suguta does her voice. Suguta is known for her roles as Marin Kitagawa from My Dress-Up Darling, Toko Kirigaya from the BanG Dream! franchise, and Haruka from Afterlost.

Guinaifen's kit, as a Nihility character, plays around the Burn effect. She also inflicts a unique debuff, causing enemies to take even more DoT damage on top of the Burn that she already inflicts. You can read more about her kit here.

Guinaifen is expected to be playable on Honkai Star Rail Version 1.4. Following the usual cadence of 6 weeks per patch, this would be on October 4, 2023. This patch is also expected to bring two other new characters, Jingliu and Topaz & Numby.