Dengeki Bunko FIGHTING CLIMAX - Shana vs Asuna Gameplay Teaser TGS 2013 (電撃文庫 FIGHTING CLIMAX)

Recently at Tokyo Gameshow 2013. Sega and Ascii Media Works announced Dengeki Bunko Fighting Climax, a 2D fighting game that features characters from numerous Dengeki Bunko light novel franchises that's currently in the works.

Playable Characters
Shana (Shakugan no Shana)
Asuna (Sword Art Online)

Also with Wilhemina (Shakugan no Shana) and Leafa (Sword Art Online) shown in the screenshots, their role in the game is currently unknown.