Yeouwa Bullocho

In order to help the nine-tailed fox find the elixir of life, the fox demon 'Seoyo' sneaks into the palace. But who appears in front of Seoyo, who was wandering around looking for the magical herb? A girl called 'Elixir of Life'?! Seoyo, curious about the human elixir of life, begins to hover around her, and the two girls begin to open their hearts to each other...

(Source: Peanutoon, translated)

Note: Chapter count includes a prologue