Fujiwara no Mokou

Formerly an ordinary human, Fujiwara no Mokou became an immortal being after drinking the Hourai Elixir roughly 1300 years ago. Now she is unable to die, though she can still feel the pain of injuries as a normal human does. She does not age, she'll never become ill, she is entirely self-sustained (nourishment such as food, water, or sleep does not impact her body at all), every injury she sustains shall cease; critical injuries will be healed in a matter of days. Complete destruction results in an immediate and complete restoration. This makes her completely indestructible, and it extends to her mental and spiritual states just as much as her physical state, as she is shown living a carefree life free of mental exhaustion even after 1300 years. She will never be able to die.