Undeniable

Loki has lost nearly everything, his mother, the love of his brother and father, even his hopes at the throne. All he has left is his mysterious adopted sister, Helda of Asgard. Growing up as siblings, but it all changes after Helda discovers her true lineage, the true daughter of an ancient eternal named Sirse. This forever changes the bond between her and Loki, becoming closer in ways they cannot control or understand. Helda grows up at an alarming rate, becoming a cunning fighter and stunning dancer with the help of her 'brother', but all of a sudden she is imprisoned for a real reason not revealed to her. Loki's growing affections do not go unnoticed by the king and his older brother Thor, who are both willing to sacrifice the young princess to keep the throne out of Loki's grasp.

Loki's guilt never ceases, and neither do his attempts to find her. He locates the tesseract to not even realizing how close he was. Thor regains the stone to keep Helda imprisoned, but after many years Helda breaks free, but with a great price. She becomes the host of the blue infinity stone bound by the energy of the tesseract, now bound onto her godlike form. It gives her powers over the Rift, an ethereal like dimension, but makes her a prime target for Thanos and a key player in the fate of the infinity wars.

Loki is threatened by Thor and Odin: Keep the secret of her imprisonment, and she stays safe from her own anger and Loki's devilish affections. But what could happen if she learned the true reason of her exile? Perhaps she could feel something for Loki as well, something so primal...so...undeniable.

Just a note: In mythology Loki ends up with the goddess Sigyn but I am taking my own twist on his story. This story was also started before the new Thor 3: Ragnarok was released so they will probably go on different story lines. Helda is my own character and not at all part of the original mythology.