Sousou no Frieren

Season 1

Frieren is an elven mage and former member of the adventuring party that defeated the Demon King and restored peace to the world after a ten-year quest. But because she has lived for over a millennium, time flows differently for her. When Himmel, the hero of her group, dies of old age before her eyes, Frieren comes to the painful realization that she never truly knew him. Haunted by regret for not having taken more interest in him, she decides to set off on a new journey to better understand the world and the people who inhabit it.