I had to. It was one of those plot bunnies that just latches on and won't go away.
This is largely based on mythology (at least what could be inferred as being in the film), especially for Sigyn. I think she's so interesting in the myths, staying by Loki no matter what, even to the end. Look her up.
A/N: I did take some liberties with her lineage, as none is actually stated in the mythology, and some later information on her life is pulled from the comics.
Disclaimer: I own nothing, especially not Thor and the Avengers.
"Love consists in this, that two solitudes protect and touch and greet each other." - Rainer Maria Rilke
Loki Odinson, prince of Asgard, was too young to remember the opposing feelings of joy and grief that accompanied the birth of Sigyn, daughter of Brynjar and Unnr, as Unnr left the world of the living as her daughter entered it. The death of his beloved wife broke Brynjar's heart and left him suffering for months. When he emerged from his grief, he set to lavishing his only child with gifts and love at every opportunity. This should have made Sigyn spoiled or rude or snobbish. It only made her kind.
The princes of Asgard, Loki and his elder brother Thor, knew Sigyn from a young age but not well. Being a child of the court, she was introduced to the boys early on, but it was several years before Loki truly met her.
It was in a summer of Loki's youth (he would appear about seven to Midgardian eyes) that he found her. Some of the other boys, friends of Thor, had been taunting him, so he fled to the sanctuary of the royal gardens. Once there, though, he heard a light song drifting through the gardens, carried on the wind. Loki followed the voice until he reached a small pool, and it was there he saw her.
Sigyn was only a few years younger than he (still looking around seven as Asgardians age differently). Her hair was the color of summer wheat, her eyes as blue as the clear sky, her skin as pale as the winter's first snow. She was singing in a clear, light voice, her fingers deftly weaving a crown of flowers from brightly colored blooms. He moved closer to her and snapped a twig. She stopped singing and looked around, calling out, "Hello? Who's there? Who is it?"
"It's only me," Loki said, stepping from his hiding spot, "I was listening to your song."
She visibly relaxed, replying, "Oh, Prince Loki. Hello. What brings you here?"
"Some of the other boys were taunting me, so I came here to be alone."
"I could leave if you like."
"No, please don't. I'd love to hear more of your singing."
"Oh, no, you don't. It wasn't all that good really."
"Yes it was. It was lovely."
Sigyn smiled at him and continued her song. It was old, a folk song about a man returning from battle and his wife's joy at seeing him alive and victorious. Her song finished with her wreath of flowers.
"Why did you pick that song, Sigyn?" Loki asked.
"It's a happy one. I sang it because I was sad, and it's hard to be sad if you're singing a happy song. I should be happy today, anyway."
"It's my birthday."
"If it's your birthday, why are you sad? Birthdays are happy."
She looked away, at her crown of flowers, and said softly, "My mother died on my birthday, on the exact day I was born. I never knew her, Loki."
"I'm so sorry. That's so sad."
"Yes… it's strange how I can miss her when I never knew her…"
Loki couldn't imagine a life without his mother, Frigga. She was always there for him when he had a nightmare or an injury or was being bullied. The very thought of her suddenly not being there made him feel indescribably sad. He looked over at Sigyn. Her eyes were cast up at the sky.
"I suppose I can't feel too sad though. She's still looking after me, from Valhalla. At least, I believe she went to Valhalla. What do you think, my prince?"
Loki mulled it over for a moment before answering, "Yes. I believe that."
"Really? Even though she didn't die in battle?"
"Yes. She did something even braver than that."
"She died bringing another life into this world, not taking life. That's better."
Sigyn smiled at him, saying, "You're the first person to say that. No one else will answer me."
Without thinking, the words passed his lips: "I'll always answer you, Sigyn."
She smiled even brighter, and Loki decided he wanted to see her no other way. He would do all in his power to make sure she would never be sad or lonely or upset or anything but happy ever again. He started by producing a bright red rose for her out of thin air.
"Happy Birthday, Sigyn."
Please R&R! There's more to follow, and there will be some eventual spoilers for Avengers (for those few of you who haven't seen it ;)