Why Does Nobody Remember Me In This Worl

All 12 episodes of the Japanese anime based on the light novel series written by Kei Sazane. After a devastating war, humanity is victorious but when history is suddenly rewritten and the world is changed, only Kai (voice of Shoya Chiba) remembers what really happened. Alone in a new reality where humanity was defeated and no one remembers him, Kai vows to become a hero and save his people. The episodes are: 'The Boy Forgotten By the World', 'Rinne', 'The Demon Hero', 'And So, She Remembered That World', 'To the East of the World', 'Elven Forest', 'Heartless Angel', 'Heaven's Purgatory', 'The Center of the World', 'The Prophet of This World', 'Where Fate Sleeps' and 'Those Who Shatter the Endless Cycle of World Reincarnation'.