The Depths of a Mother's Love
When Loki had borne his first child, the eight-legged foal, he’d been alive a mere three hundred years; Odin had confiscated the animal for his own stables, and bid Loki be more careful with his tricks. Later, when a giantess seduced him, Loki—still young—fathered three monsters: a wolf, a gigantic serpent, and a girl with half her face as blue as a frost giant. And Odin had banished them to secret locations across the Nine Realms, providing Loki with the barest hint of where they now lived their lives.
But even centuries after they’d been separated, Loki continued to search for them, following every lead he could find; nothing ever came of it, and Sif privately thought it cruel of the Allfather to give Loki clues that ultimately amounted to nothing.
That was the extent to which she cared for Loki’s feelings; their rivalry was a long and bitter one, sparked by some long-forgotten insult or childish act that had carried on through the centuries. Perhaps, once, it had been more of a friendly war, the sort that children grow out of—but then one night, as payback for mere words, Loki had snuck into her room at night and cut off her hair. Soon after, he had further humiliated her by replacing it with a magic wig that turned her hair black—black, like Loki’s hair, rather than the golden hues of every pure-blooded Asgardian. And though no one could ever mistake her for a halfbreed, the irreversible shift in her appearance had left a bitterness inside her that grew rancid over the years.
As she bore witness to Loki’s various pranks aimed at others, she began to consider that Loki did little good for the Realm, and much harm, and that perhaps it would be better for all if he were no longer there to bother them. (Of course, Thor would not agree, but then, he was blinded where his brother was concerned.)
Then, having gotten to an age where she yearned for Thor’s attention in a way quite different from that of a friend or a shield-mate, she began to notice just how often Thor brought Loki along on every possible journey… and just how often he chose time with his brother over time with her. And her bitterness found its tipping point.
Enough decades had passed that Loki trusted her again, more or less, and so she came to him one night, and told him that she had had heard of a place on Midgard where a giant serpent could indeed be hidden, a place that matched the hints that Odin had given him, and that if he could provide a ship, they could see if they could find his son.
The ship that folded down small enough to fit in a man’s pocket came with them to Midgard, along with a heavy trunk that Sif had brought. Soon enough they were out in open water, over the deepest part of the Midgardian oceans, the Trench of Mariana.
And when Loki wondered aloud at how he was to get down that deep, Sif opened the trunk—large enough for a man to lie in, with some room to move around—and proposed that she would lower him to the bottom, leave him there for a few hours, and then bring him back up again. While he would not be able to see anything, he could at least reach out with his mind and determine if his son were truly out there, and if they found him then they could consider their next steps after that.
The trunk was made of Uru, of dwarven construction, and would easily stand against the pressures of the deep. And where a mortal would suffocate before even reaching the bottom, an immortal had no such concerns; Loki could survive indefinitely, and had in fact survived three months in a similar chest without food or water, though of course it hadn’t been pleasant.
Still, for his son, Loki would bear much worse. And so he did not hesitate to climb into the trunk.
Then Sif locked it tight, and tipped it over the side.
If Loki had missed the fact that there was no rope attached, well, he’d been a bit distracted.
Once back on shore—for the ship’s skillfully crafted design ensured that it could be easily manned by a single person—Sif folded it down to fit into her pocket, and called for the Bifrost to bring her home. And if Heimdall thought anything odd about the fact that she’d gotten to Midgard without using the Bifrost to begin with, well, he did not care to comment.
A couple days passed before Thor noticed his brother’s absence, but he merely groused about how Loki would run off on adventures without even telling him. Then he easily got distracted into another activity, and went on with his day, expecting that Loki would return when he was ready.
Privately, Sif wondered just how long it would take him to truly feel the absence of Loki in his life. But whether he clung to her in his grief, or invited her on the quest to find Loki, or simply spent more time with her because he had forgotten that Loki ever existed, in any case she would finally have her Thor.