There are nine realms that compile the great tree of Yggdrasill. Each root and branch of the tree connects the worlds in single purpose. With every world, new creatures reign, people live and die; love fades or prevails. The tree itself was created by the Fates, fed upon by the terrible monster Nidhogg, nourished by the waters of wisdom in Mimisbrunnr; all the worlds within the tree are a source of grand life and beginning. The greatest of these worlds, Asgard, lies at the very top of the tree, unifying and protecting the realms from dark forces outside of Yggdrasill. On Asgard, the protectors move about each realm by aid of the Bifrost. This grand rainbow bridge transports to any place in the universe of Yggdrasill, though this travel is only allowed by the gatekeeper Heimdall.
Thor led the best warriors of Asgard to Jotunheim in the wake of a clandestine attack by a few frost giant soldiers. During a skirmish with the frost giants, Thor's brother, Loki, was not harmed by the enemy's touch, while the rest of those fighting suffered great cold burns at even the slightest contact. This discovery of the Prince's true paternity, son to the now deceased frost giant Laufey, sent him into a furious rage over the royal house in Asgard. Loki subsequently attempted to destroy Jotunheim and all its inhabitants, and Thor Odinson himself destroyed the Bifrost. Without a means to move between worlds, Asgard was separated from the realms as the Bifrost was rebuilt.
But not all Asgardians use the rainbow bridge to move among realms. The great tree did not intend for any one world to be separate from another. It left tremendous energies in small places, accessible only by the most cunning of folk, allowing the connection among worlds to remain constant and unchanging, without the aid of machines. The sorcerers of the highest worlds know of these portals, acknowledged by so few that they cannot be documented. Only these great magicians, such as the exiled Prince Loki Laufeyson, can navigate the portals safely.
...
The realm of Vanaheim is home to the old Vanir gods, true magicians and masters of sorcery. Their love and care for their world, and the forests and waters that run freely through the landscape, echoes in their care for one another. This realm, to the west but not far from Asgard, holds respect from the remaining realms but is not guarded by true law or rulers. It is a peaceful world, if not one trusted to remain self-contained.
Loki is still holding Sigyn's hand as they exit the portal onto an expansive, green pasture. There are quiet, small, funny looking birds flittering above their heads and into the tall trees. His steps are labored and painful; Loki can cast a façade upon his facial burns but cannot mask the sores on his feet. He looks longingly at Sigyn, his expression showing gratitude and guilt, as they keep walking. Their destination is nowhere; they are exiled from their home.
"We should be safe here," Loki whispers, not sure if he is comforting himself or the woman beside him, leading her underneath one of the larger trees. He contemplates the last few months of his life: finally acting as the true Asgardian King, revealing himself to this innocent maiden, perhaps even falling in love with her, and now facing this fate as a fugitive. Loki questions his motives for keeping Sigyn alive, or for allowing her to suffer for his sake; why did I not take action when I first met her? Why did I not make a swift strike to end the possibility of discovery?
As Loki's eyes fall upon the ground, seeing again the meager coverings she fashioned for his injured feet, he knows the answer. Loki knew he could trust her, and that she would take care of him, as his mother once did before she was murdered in that same chamber. I am indebted to her, he thinks.
"Where are we, Loki?" Sigyn searches the landscape for anything familiar, but this place is so unlike Asgard. Without tall, golden towers of a city, she cannot mark a direction. Sigyn is struck with a different gray moon in the sky, which is rising quickly. This place is beyond foreign to her, and she feels a pang of emptiness in her chest. This world is not her home. Sigyn can't bear to admit the pain she feels to know her precious cat, Tiwaz, will be forever searching for her.
"This, Sigyn, is the realm Vanaheim," Loki presents the open field to her with a gesture of his arm. His eyes feast upon the ever-spreading scene with wonder and happiness, glad to be in a place where he is unlikely to be viewed a villain. Loki has been to this world before, though not since his youth. He remembers the Don City, an old stone fortress of Vanir gods and goddesses, who practice magic and tricks with one another in the streets.
"Vanaheim was my mother's home once, before coming to Asgard after the Great War. She taught Odin all he knows of magic..." The revelation gives him pause, and he continues quietly: "She taught me all I know as well." Loki's eyes become hot and itchy with the memory of holding his mother's hand as she walked him through the corridors of the Don City, and recalls the contrasting cold of the river that ran through the center. While Odin and Thor valued strength, Frigga valued the skills of her homeland, and saw the potential in Loki even as a child. She brought him to Vanaheim to teach him the ways of sorcery, granting him the ability of illusion and shapeshifting. It was Frigga's hope that Loki could shine in his own right with the skills he so naturally learned from her.
"Why did you want to come here, of all places?" Sigyn is ignorant about the other realms of Yggdrasill, knowing so very little about any world outside her own. She is feeling homesick but free as well, knowing that she undoubtedly missed a feast for the assumed death of Loki back in the great hall.
Loki looks at Sigyn, and holds his hand before his face. With a simple gesture, the façade he cast upon himself is wiped clean, revealing his burns to her for the first time. Sigyn was so consumed with holding the venom above him on the rock that she could not see the damage it had done. Even in the single-tone moonlight, Sigyn gasps at the sight. Loki's eyes are stained with red. His cheeks are nearly worn through to the bone. The now short hair is matted to the side, where it was protecting another open gash that he caused while thrashing in pain. Loki again swipes to the front, restoring his healthy appearance so as to not cause her more worry.
"I am deeply injured, Sigyn. I see now that you are as well." Loki points to the sores on her knees and the gash on her leg, which was worn in while she turned back and forth to empty her bowl and get him covered. "Let us hope we find a friend here in this world to help us." Loki stands again and holds his arm to Sigyn, still carrying his green cape at her side. They walk towards the gray moon ahead, not sure of what they will find in the Don City now, if they are able to find it at all.