One idea could be that the characters from SAO find themselves in the world of Ghost in the Shell. They have to adapt to the high - tech environment where cybernetic enhancements are common. Kirito could use his sword - fighting skills in a new context against cybernetic foes.
Perhaps in this crossover, the technology from Ghost in the Shell is used to create a new type of virtual reality in SAO. The characters then have to deal with the implications of a more integrated physical and digital world. Asuna might struggle with the new level of surveillance and control that comes with such advanced technology.
Another plot could involve a character from Ghost in the Shell getting trapped in the SAO virtual world. They would bring their knowledge of advanced hacking and cybernetic combat. The two groups of characters would have to work together to find a way out, with the SAO players learning about the real - world implications of the technology they are using in the game.