Naruto: She's Watching You

[Original female lead]

Uchiha Mayumi was a wandering ghost in the mortal world.

One night, she was resting in the clan compound

when she sensed an old friend's presence.

Without hesitation, she rushed out.

Sakura Haruno was a student about to graduate from the Ninja Academy.

That night, she had planned to investigate the history of the Uchiha,

but a female ghost charged straight at her,

and she ran forward with all her might.

The story is more or less about the female lead teaching Sakura to become an elite jonin, while discovering the ultimate meaning of her own existence.