Devils' Crest - S01

Sixth-grader Yuuma Ashihara and his twin sister Sawa are playing Actual Magic, a brand-new virtual reality MMORPG, when it suddenly starts to merge with the real world. In all the chaos and confusion, it becomes clear that death waits around every corner, including when Yuuma runs into his classmate Sumika. She used to be one of the cutest girls in his class, but now she has gone through a terrible change and become one of the game's horrifying monsters.