This is sort of like Princess Resercretion. How the siblings all have to kill each other for the thrown and the last one standing wins.
Full Summary:
Amu is hiding her identify from her past life. Her real name is Amulet Hinamori, the sixth child of the Kaiju Realm. She is supposed to kill all nine of her siblings if she intends to live. If she doesn't, they'll kill her. The last one standing gets the thrown. Only problem is, Amu doesn't want to kill her siblings. Her solution: at the age of eleven she ranway with her youngest sister, Ami. In order to remain hidden and unknown she made herself appear two years younger and enrolled in to primary school, although she should be in eighth grade going on to nineth. She changed her name, her age, her style, and her attitude, all in hopes that she could never have to return to that terrible place. Of course, she wouldn't get her wish. Her father, King Emma, king of the Kaiju Realm takes her Humpty Lock on first sight and demands her and the rest of his children to go after the Dumpty Key, which Amu's love of her life, Ikuto Tsukiyomi, owns - and when they find him, he'll be slaughtered i fhe resists (which, of course, he will 'cause he's just Ikuto).
(I know it sounds kind of if-y, but if you could, please give it a chance. I promise it's actually interesting.)
A loud buzzing of an alarm clock caused a sleeping, pink haired girl to yawn awake, slapping the annoying yellow devise.
Amu Hinamori stood up, stretched out her body slowly, while rubbing the sleep out of her eyes. She looked behind her on the desk, finding her shugo chara's basket empty with the exception of Dia's egg, which she never comes out of.
"Huh? Ran? Miki? Su?" Amu asked sleepily.
She looked through the basket not find any trace of her pink, blue, or green eggs.
"Where could they be?" she mumbled.
Amu started looking around her room, trying to find out where her colorful eggs had gone. Under the bed? Nope. Pillow? Nope. Behind the computer? Nope. In the bathroom? Nope. In the kitchen? Nope. With Ami? Maybe… Nope. Living room? Nope.
Immediately Amu started to panic and went on a throwing frenzy. Looking every spot in her room, not an inch of it went untouched.
"Urgh!" Amu yelled after about thirty straight minutes of looking for her eggs. Pulling her hair in frustration, she looked around her now completely wrecked room, not finding any trace of her shugo charas. "Where are they?!"
"Huh? Where are who, Amu-chan?" a yawning Dia asked, flying out of her egg.
"Ran, Miki, and Su. I can't find them anywhere."
"Them? They don't exist anymore, Amu-chan. Remember?" Dia stated matter-of-factly.
"What?!"
"Yeah. They disappeared. They don't exist anymore. Remember when you first got them? Shugo Charas can appear out of nowhere one day and the next they're gone."
"W-What do you mean? Don't… exist?"
"Aw, cheer up Amu-chan! Remember I'm your navigator!" Dia said cheerily, flying up high.
"N-Navigator? What are you talking about, Dia?" Amu asks wearily.
"Navigator to the future, of course!" Dia said, grabbing on to the Humpty Lock, and handing it to Amu. "Here, hold this! Now, let's go!"
"Character Transformation: Amulet Diamond!"
A now golden Amu dressed up in her diamond chara nari costume looked around the room, skeptical.
"H-Huh?! What are you doing?!"
"Starlight Navigation!"
"Come, come, Amu-chan, let's go to the future and get Ran, Miki, and Su!" Dia shouted.
Behind her was a whole world of stars and bright lights. Should Amu really do this? A few trails of star dust formed a make-shift road.
"Don't you want to see Ran, Miki, and Su again, Amu-chan?" Dia asked.
"Yeah. Let's go!"
Amu hesitantly stepped into the star filled world only to be swept away.
Sorry, I didn't really go into detail on the whole "Starlight Navigation" thing. I'm too lazy. If you want to know what I was typing, go to onemanga,com and look for Shugo Chara chapter 45. You'll understand this more. Only difference in the manga and my story is that I'll be cutting away the scenes where Amu goes sees Ikuto and all of that other jazz. She ends up in another realm all together, okay?