The Codex Runicus, a law code written in runes (c. 1300 CE)
Odin looked up at the world tree. Yggdrasill's bark was golden-brown, and the tree towered high into the cosmos. Of course, he could only see a third of the way up because a thick canopy of black clouds separated the worlds. Above this were the middle realms.
Not far away from Odin was a well. This belonged to the Norns. It was the Well of Fate. If he followed Yggdrasil's second root, he would come to another well. Mimir's well. Odin remembered all he had sacrificed when he was last there, but he also remembered all he had gained.
In the distance, the sky crackled. Muspelheim, Odin thought. While the fiery infernos still tore through it, ever since Yggdrasil came into being, they had not strayed as far into Ginnungagap as they once did. The bitter blizzards from Niflheim had not strayed from their realm, either. Yggdrasil, it seemed, had separated the two realms and brought order to the chaos.
Odin went up to the world tree and began to climb it. It would take many days before he reached the top. He would need to pace himself. The quicker he climbed, the sooner he would become fatigued. But if he took too long, he would starve to death. He had, after all, brought no food with him. This is the way it had to be, though. He had seen it in a vision. Only by pushing himself and reaching the top of Yggdrasil could he learn the runes.
The more he climbed, the more the skin on his palms became sore and calloused.
As he approached the cloud boundary, the weather turned icy. He could feel the colds sweep over him. They gnawed at his joints and clawed at his bones.
He gritted his teeth and continued climbing.
Once he was above the cloud boundary, the weather suddenly changed. The sky became much lighter, and the colds became less harsh. He could hear the wind whistling around him. He was in the middle worlds.
Now that he was a third of the way up Yggdrasil, it began to branch out. Odin could wedge himself between one of the thick branches and rest.
He looked out over Midgard. It was as beautiful as he remembered; the roaring sea, the jagged coastlines, and the grassy fjords. One day, he would return here.
He stood for a while, gazing wistfully at his surroundings.
When he felt ready to continue, he began climbing Yggdrasil once more. High above him was another canopy of cloud. This time, though, they were white. Above these clouds were the higher realms; Vanaheim, Alfheim, and Odin's home, Asgard.
As he climbed higher, a squirrel with a scarlet coat scuttled by. It paid him no heed. It had its own duty, after all. This was Ratatoskr. The animal that delivers messages from the hawk perched atop Yggdrasil down to the dragon that slivers at the bottom of the tree.
Odin was growing weary. It felt like an eternity since last he ate or drank. The winds had become more and more violent. They whirled around him and crashed into him. It jerked him from side to side. To keep himself from falling, he had to concentrate on his footing, to tighten his grip around the branches. His only solace was the warm rays of amber sunlight that trickled down from the higher realms.
When he was finally above the second cloud boundary, the wind died away and was replaced by a gentle breeze. A wave of warmth washed over him. He could smell the piny aroma of the woodlands. This was from the emerald forests of Alfheim, the realm of the light elves.
Opposite this was Vanaheim, the realm of the Vanir. He remembered the first war, all that violence and bloodshed.
The sky above him was bright with golden sunlight. The sun was so intense from this high up that it was blinding to look at. Rumour had it that the Asgardian sunrise is bright enough to turn a dwarf into stone. When Odin felt safe enough to remove one of his hands from the tree, he pulled his hood over his head.
He was now so high that he would soon reach Asgard, home to the Aesir. He could see it above him, a sprawling city atop a sea of clouds. At the far end of the city was a waterfall, which cascaded to the worlds below.
The world tree rose straight through the heart of Asgard.
Once he was high enough, Odin glanced at the gleaming halls of Asgard. He could be in one of those halls right now, drinking mead and eating meat. Instead, he was ravaged by hunger and riddled with pain. His hands were bruised and bloody.
Still, he pressed on.
The top of the tree was now in sight. There was no longer a thick trunk to hold onto but a tangle of branches. He grabbed onto one of them and pulled himself higher.
When he eventually reached the tree's highest branch, he had grown so weak that he drifted in and out of consciousness.
The hawk that perched on the top of the branch watched him. Its feathers were brown, and its beady eyes were black. To Odin, though, it was nothing more than a blur.
As Odin tried to drag himself further up the branch, his eyelid grew heavier and heavier. And then, finally, it closed.
Odin fell limply from the world tree.
He plummeted through the higher worlds, gaining momentum with each second. When he came to the cloud barrier, he passed through it like a pebble that had been dropped into a vast ocean. He hurtled through the middle worlds and then through the cloud boundary into the lower worlds.
He landed at the foot of Yggdrasil. His broken body was motionless.
He lay there for nine days.
When he awoke, he felt different, as if something inside of him had changed.
He got to his feet and staggered over to the Well of Fate.
The Norns had scratched runes onto the stones around the well. Odin knelt in front of one of them and looked at it.