I do not own Katekyo Hitman Reborn nor Harry Potter
...
Prolouge
She supposed it was a curse, gathering all three Hallows and being the Mistress of Death. Even if she was granted immortality and eternal youth, it was with a terrible price that no individual should experience.
She had outlived all of her friends and loved ones, had watched or heard news of them falling one by one.
First it was Mr. and Mrs. Weasley who both died peacefully in their sleep. Then it was Bill who was hunted by the remaining Death Eaters, Fleur who died of defending him in court, Percy, who had died during a mishap in the Ministry, and his wife Audrey due to grief.
And she couldn't bear to watch, because Harriet Lillian Potter knew, that she, as the bloody Mistress of Death, would not (could not) die.
She was forced to watch as everyone succumbed to suffering as the remaining Death Eaters managed to gather all blood purists and released Basilisks with only one order.
Kill those who walk bearing magic with impure blood
And she tried, tried to tell them, tried to help, but she can't
(As the Mistress of Death, you can see everyone's 'deadline' or timer, Death said)
Strong and loyal Ron, defending the whereabouts of his family till death. Taking an Avada Kedavra to the chest as he was ambushed getting to work, his mind at peace knowing they wouldn't get to his family who had relocated at America.
(Their timer is shown directly above their heads, like a video game)
Sweet and Calm Neville slowly succumbing to a rare sickness while traveling in Australia, unable to find a doctor and having his magic depleted.
Aloof and Wise Luna somehow getting involved in a fight between a pack of gryffins and a mother dragon, her body found floating serenely in a lake.
(Your job is to make sure they do not surpass the deadline, easy right?)
Warm and Mischievous George, 'pranking' the remaining Death Eaters and going out with a bang as he took out a third of them within the confines of his own house after his family evacuated.
Wild and Fierce Ginny taking down an entire hideout and collapsing in the middle of the hospital as she apparated with cuts and bruises littering her body, along with an old curse taking over her heart.
(And don't forget, you can not intervene when their time is up)
Bold and Stubborn Hermione falling into grief when she heard the news. Her timer slowly coming to a stop after the funeral, leaving behind even more grieving and loss of hope.
And Teddy, her sweet, sweet, Teddybear, died while on the run. A fellow runaway overdosing him with Sleeping Draught as they left him in the cold.
(I hope you the best, Mistress)
"What more do you want?" Harriet whispered as she watched the Wizarding World slowly crumble because of each other, each generation producing more squibs than the last.
She watched as bile creep up her throat, her eyes glossing over with tears as she watch her world crumble, a world that was once her hope, a world that she swore to protect. She watched as each wizard and witch throw out curses and hexes with the goal to kill, to maim, to destroy, and it hurt.
"I have a proposition for you Mistress,"
And she looked at Death, glared as she saw the reason why she can't help, why she can't stop them and- and- she wanted to kill him, wanted him to disintegrate, make him pay, weep and–
"Do you believe in Reincarnation?"
And as she calmed down and listen to the proposition. She took a long look at the destruction surrounding them, remembering memories from what was long ago, and-
"Do it"
Because she was Harriet Potter, Girl-who-lived, The Chosen One, and the Woman-who-Conquered. And she swears on her magic and on her knowledge-
Whatever life I may come, I promise to do my best and make sure my next world would not end up like my first.
...
"You are to be reincarnated in a world of my choosing, retaining your knowledge and magic, along with a reincarnation of a loved one who will not retain their magic nor remember his or her former life"
"Do you accept, Harriet Lillian Potter, Mistress of Death?"