With Dani's Army Of Mini-Sloths And My Ninja Skills, The World Could Be Ours!!

Challenge ten - (Kid version) Saving you parents from monsters under the bed.
I had fun with this, because the little girl in the corner actually looks like me from when I was younger. By the way, this is a LONG story piece.
xXx
He'd left her so that she could visit her grandmother, he knew that she'd never live down him hearing her called 'Firefly child' by the elderly woman but he let it go. For now.
He'd arrived here at this small cottage and found the child, curled up in the corner of the garden.
"Are you alright?" He asked gently, crouching down so he was level with her.
"I'm as alright as a child in a garden during the rain can be." She squeaked up at him and he smirked, holding out his hand.
"Perhaps," He suggested, "You should come inside?"
The girl considered this, and nodded, taking his hand and practically leading him inside.
xXx
"Monsters under the bed?" He asked, and she nodded holding a necklace tightly in her hands.
"But I'm not scared!" She told him sternly and he smirked at her from where he was, peering under her bed.
"It's trying to make me mean, but I'm not mean so it's rubbish."
The doctor stared at her, peering around the room.
"What's that necklace?" He asked and she held it out to him carefully.
The doctor stared at it, and up at her. He'd never discover where a child got a crystallized piece of weeping angel, but she was safe now that he'd exchanged it for another.
"Thank you Mr." She called to him and he shook his head.
"I'm the doctor!!" He called to her as he walked to the tardis.
"I'm a firefly!!"
He'd never understand children.
xXx
"Hey doc!" Ashleigh called trotting up to the tardis without a care, he really liked that about her. Liked the fact that Ashleigh was always so cheerful.
"Sorry I took so long, had to get this." She called, holding up a necklace.
"Remember this?" She grinned, pressing it into his palm and leaping into the tardis without a word.
It was her necklace, the little girls.
The Doctor hadn't felt quite so light in a long, long time.

Avenger story set.
Who is she?
 
xXx
 
The group stared through the one-way window at her, and it was Loki that was compelled to speak first.
"You are saying, that...that child, is immortal?" He asked and Fury nodded.
"That's why she needs to be placed in protective custody" Fury explained and Steve frowned.
"We need to protect her" He pointed out.
"You need to protect her"

An avengers story piece including Loki and an OC. Enjoy!