In Pokmeon Mystery Dungeon Blue there is a legend about a human who pulled the tail of a Ninetails. This human had fled when his pokemon had sacrificed herself for her ungrateful trainer. As punishment for pulling Ninetails' tail and for abandoning his pokemon Ninetails turned him into a pokemon.
Now why did I have to point this out you may wonder. My point is if Ninetails can turn an evil human into a pokemon. Can't Ninetails also turn an evil pokemon into a human?
And in the game to me it seems the game mildly points to your nasty rival, a Gengar. I think he was the evil human that abandoned his pokemon. But as far as I know, I haven't taken the time to replay the game and refresh my memory on it, it never point blanks says who the human was.
This story is like that. There is little to nothing about being a Rescuer. But this story is about a Hoothoot who made a bad call and was punished with an uncanny curse. The Hoothoot was cursed to float between the two worlds. Until she found those she wronged and makes amends for her crime. She guards a perfectly circular lake called Moon's Mirror.
*Two Decades Ago*
Ninetails: Luna…you have been tried in a court of law and found guilty.
Noctowl: Please Ninetails! Be merciful! My student meant no harm. Luna happens to be a bit clumsy. Tell her Luna! Tell her it was an accident!
The Hoothoot, called Luna, stood before the counsel of the six Noctowls and Ninetails.
Luna: …Accident or not…someone died because of my clumsiness. I am guilty as I pleaded Master. And I will take the punishment Ninetails gives me without whining.
There were tears in Luna's eyes as she stood firm knowing the punishment would be awful fate.
One of the Counsel Noctowls: As you wish Luna. If you have any last wishes or unfinished matters speak up or forever hold you please.
Luna: Yes…I have only but two things…
Luna turned to her beloved master who had bravely stood by her through this trail without doubt.
Luna: Master I leave my family in your care. And thank you for being there for me all these years. I know I have not been an easy student with my clumsy mess-ups and being slow to learn new things. I only wish I could have been the star student you deserved.
Luna's Master eyes started to water as he wrapped his wings in a protective teepee to both hide his sorrow and to embrace his beloved student for the last time.
Luna: And lastly, Master please don't cry when I'm gone. Get another student to teacher the art of map making. The Recuse Teams and pokemon all over the world need your maps.
Luna smiled up at him from the shadows casted by his wings as the moonlight leaked in between his feathers. Her smile broke him; his tears fell silently on Luna's head feathers where they seemed to melt away. Yes while it was true that Luna was a lot of trouble and hard to handle at times. It could also be said that she was very loving and sweet. She worked hard to do her best even when her best wasn't enough. She learned slowly, but she worked hard make her Master proud. It was her strong spirit in a weak body that her Master loved the most; her hard working nature.
Noctowl: I will take care of your family, and I will not give up on making maps for pokemon in need. And I will do it because you asked me to. I have never been very personable with former students of mine. But my former students weren't like you. You're special Luna. Not it in power or mind, but in here.
Said her Master as he points a feather to his chest where the heart is located.
Ninetails: Are you ready to hear my sentence now Luna?
Luna nodded
Ninetails: By the power I was born with I sentence you to be cursed.
Everyone in the room gasped while Luna froze in horror.
Ninetails: From this day forward you will be guardian over a lake called Moon's Mirror. But you will not do so as a pokemon for you have defiled the world of pokemon. You will protect the lake as a being floating between two worlds. You will be human but still be pokemon a bit. In this way you will find no comfort in the human or pokemon world. You will be alone, and on your own. To break this curse you must find the one you victimized and make amends with them.
You will have no memories of being a pokemon but you will remember that you were one and that you are cursed for a crime done to you. The old you will be washed away. A faceless female you will walk in the two worlds.
Victim must state what it would take to pay back for their loss, even if that means your death. If you do not make amends you will forever be trapped as a human. Death will not let you rest until you have paid for your crime. All the while you must guard Moon's Mirror. You must not abandon the lake at night when there is a new moon. If you abandon the moon you will come to know a darker fated then death.
Ninetails growled lowly at the last part. Being turned into a human was the ultimate form of banishment. This punishment would forever change Luna's life.
Luna nodded her head while the room exploded in argument. Ninetails glowed with an aura of many colors, the words of the pokemon faded in Luna's ears, as the world went dark.