I Came Back from 9,000 Years Later

Ling Shu, the last phoenix, travels 9,000 years back in time to find her great-grandmother Tang Tang—the "love-obsessed" ancestor who lost their clan's sacred seed and got the phoenix tribe cursed. But as Ling Shu gets close to Tang Tang, she uncovers the truth: the seed wasn't given to a demon lord for love.

It was used to save villagers from a plague. She goes from stopping Tang Tang's romance to understanding her sacrifice and ultimately gives herself up in rebirth to redeem her bloodline.