あらすじ
"I can’t believe my past self was so into this embarrassing nonsense!" In middle school, Tsukasa Hizaki was summoned to another world and became a legendary hero, saving the world by defeating the Demon King. After his victory, he was forcibly returned to modern Japan, where he spent three years trying to live a normal life… until he was summoned back once more. His new mission? Stop the rampage of the secret organization "Helheim." But there’s one problem—Helheim is an evil group that HE himself created during his cringeworthy chuunibyou phase, where he called himself the "Corpse King." Someone is now using the name of Helheim to spread terror, and Tsukasa is determined to clear his name. To do so, he must reassemble his former lieutenants, the legendary "Eight Commandments," and unravel the mystery behind the imposter. First stop: The Steel City of Gagiul, where a famine-stricken town and a desperate noble lady await his aid. "Helheim, mission start!"