Bandai Namco announced that Neige will be a free character for folks to earn in Sword Art Online Fractured Daydream, however she is locked behind the SAO Extreme Boss Raids and Neige Fragments. She is a season 5 character alongside Spriggan Kirito, who is being sold in the in-game shop.
Neige is an original character who debuted in Sword Art Online Fractured Daydream, who supports the other original SAO character Fuuka throughout the game. (Fuuka was also released as a free character, and we needed to finish the Main Story Quest to get that Mage.) The announcement confirmed she will be a Tank and be voiced by Mariya Ise, just as she is throughout the campaign. Her teaser image also noted she can be used as a Support in some ways, due to the auto-guard effect of her Extra Skill.
Meanwhile, Spriggan Kirito is based on his ALfheim Online appearance. He is a Rogue.
Here are the teaser images for both Neige and Spriggan Kirito in SAO Fractured Daydream:
There is also a trailer highlighting what this Rogue version of Kirito can do in a fight.
Sword Art Online Fractured Daydream is available for the PlayStation 5, Xbox Series X, Switch, and PC worldwide, and season 5 started with Neige and Spriggan Kirito.