Tensei Daiseijo no Mezame ~Shouki wo Joukashi Tsuzukeru Koto Nijuunen, Okitara Densetsu no Daiseijo ni Nattemashita~

The hero party defeated the Demon King who threatened the world. However, on the brink of death, the Demon King released a miasma that would bring about the world's destruction. As everyone despaired, the Saintess Sophia succeeded in halting the Demon King's miasma by sacrificing herself. Time passed, and what awaited her upon awakening was the world twenty years later. While she's bewildered by former companions now being middle-aged men and juniors having become older than her, Sophia lives on in a world that has become peaceful?