Tensei Daiseijo no Mezame: Shouki wo Joukashi Tsuzukeru koto Nijuunen, Okitara Densetsu no Daiseijo ni Nattemashita The Awakening of a Great Saint: Waking up as a Legendary Great Saint after Twenty Years of Miasma Purification

Synopsis

The Party of Heroes defeats the Demon King, a menace to the world. But as the enemy meets his demise, he unleashes miasma capable of destroying the entire world. In the face of despair, Saint Sophia makes the ultimate sacrifice to halt this devastating miasma. Years roll by, and when she finally awakens, she finds herself in a world twenty years into the future. (Source: Kodansha USA)