Legend of Legends: Demon's Ascension

[Have you read Legend of Legends? Yeah, something like that, but in japan with a thicker real world plot (HA! as if!). Probably worse too. (Most likely worse)] A loner is the right definition for Ahmya Yozora, an otaku that isolated himself from other people, his hobbies getting him dirty looks from his classmates. Now, with his parents working overseas, he inherits the dojo from his grandfather that raised him with a bamboo sword in hands. And it's here where our story starts, when a new disease, abnormal narcolepsy strikes the world. And now it's time for him to struggle for survival as a minion, fighting in the Valley of Fallen Heroes!