Demons' Crest, Vol. 1 (light novel)

Yuuma Ashihara is playing Actual Magic, a virtual reality MMORPG, when it suddenly begins to fuse with the real world. While he tries to make sense of what-s happening, he runs into Sumi, one of his classmates. Before, she was one of the cutest girls in his grade, but she-s undergone a terrible metamorphosis-into one of the game's monsters! From the author of Sword Art Online and Accel World comes a story beyond VR and AR, where game and reality are one and the same.