Either not hearing or ignoring Atticus' question, Thanatos continued through the door into the same hallway that had brought them to Hades. Fearing to be left behind with Cerberus, Atticus decided to let the question die and made for the doorway himself. Thanatos had already passed several doors by the time that Atticus had caught up to him and was standing before one at the end of the hallway with strange, blocky script above it.
Thanatos put a hand on the doorknob and looked over his shoulder at Atticus. "I should warn you; this place is quite a bit different than what we just saw in Hades. Don't be alarmed if someone throws an axe or two at you." With that, he turned back to the door and opened it wide. From the doorway whistled air colder than Atticus had ever felt before and a cool, blueish light came from the other side. Thanatos stepped quickly through and Atticus followed along shivering. On the other side of the doorway was an icy track which led through a snowy field. Steep mountains rose in impossibly tall ranges all around them, their peaks disappearing into the clouded sky above.
Noticing Thanatos ahead of him, Atticus sprinted to catch up. "What's the rush? We didn't go this fast in Hades!" Thanatos threw a glance to Atticus and answered without stopping. "Two reasons. One: it's cold here and I don't like it when my wings freeze. You wouldn't believe what a mess it makes defrosting your feathers! Two: I wasted too much time homesick in Hades. We gotta make up time now to keep schedule. Now, let's keep moving."
They stopped a few paces later at a tee in the road. "We are in the Norse Underworld now. They lived far to the north from your homeland. They loved to fight, and their afterlife reflects that. Here, there are four options for the dead. Those who die at sea stay in the Realm of Ran. If you look to the left, that large expanse of water through the valley is her domain and those seas are filled with dead sailors.
"If you look to the right," as Thanatos pointed to a massive cave bored into the side of the nearest mountain, "you will see the entrance to the Realm of Hel. Everyone who died an uneventful life or without honor goes to her realm. It's a pretty dreary place, but not as bad as some people made it out to be in the medieval period. However, the reason you qualify for this afterlife is because you were a soldier."
"Wait, you said there were four realms here, right?" Atticus gestured at the empty valley around them. With a chuckle, Thanatos pointed up. Confused, Atticus turned his eyes upward and felt his jaw grow slack. Above them floated two massive structures. One resembled a long house made out of impossibly large trees. Beside it floated an equally large boat, yet it hung in the air upside down.
Atticus felt Thanatos grab hold of his tunic and then they were soaring through the air. "The house is called Valhalla, Odin's Realm. There they train dead warriors for a world-ending battle. They feast and drink each day as reward for their efforts in life."
They began to approach the house as Thanatos shouted, "I will show you around there, but to save time we will skip the tour of the boat to make up for time I lost in Hades. To fill you in, it's called Folkvangr, the Realm of Freya. They also prep for that big battle, but they are more chill about it than Odin is. When the battle starts, they will sail to it in that boat."
They landed just as Thanatos finished speaking. With a mighty shove, Thanatos threw the massive wooden doors wide and ushered Atticus into a scene stranger than he could have ever imagined. The room was filled with thousands of burly men with ridiculous horned helmets chugging from tankards and throwing axes around the room. As they began to make their way into the crowd, Atticus was surprised to see that many of the figures were actually women. He was just about to question Thanatos about this when Atticus saw a man in golden armor sitting on a throne which grew directly out of the tree. In his hand was a golden spear and an eyepatch covered his left eye. Beside him stood a red-haired man burlier than any in the room and, by far, with the wildest beard.
"The one on the throne is Odin," Thanatos shouted above the crowd. "He is in charge here. Better not disturb him now. See that guy next to him? That's his son, Thor. He's bad-tempered and always looking for a fight. Come on, let's go outside before he notices us." With that, Thanatos quickly began weaving back through the crowd to the door they had come from.
Once there, Thanatos turned back and asked, "So, what do you think of Valhalla? Pretty crazy, huh?" He pulled out his clipboard and read for a moment before continuing. "It looks like you qualify for Hel, Valhalla, and Folkvangr here. So, if you choose to submit to the judges of this Underworld, then you will be put in one of these lovely accommodations!"
Atticus thought for just a moment. He guessed he would likely be in either Valhalla or Folkvangr because he had been a soldier, but he didn't like the sound of possibly having to spend eternity in the cave of Hel either. Not knowing where he would be sorted, he decided that he wanted to see what the other Underworlds had to offer first.
"Let's keep going. I want to see what other options there are." Not looking too surprised, Thanatos made a quick note on his clipboard and put it away. "All the same to me. Let's move on to the next destination: the Aztec Underworld!" With that, he opened the same door to the same short hallway and stepped through. With one last look on the sunset through the mountains, Atticus followed.
This story was meant to be radically different from the Greek Underworld: more wild and rambunctious. Much of what modern historians know of Norse religion is tinted by Catholic influence, largely due to two reasons. One: almost all surviving texts about Norse religion are from Catholic sources, so are inherently biased. Two: the Catholics actively sought to change Norse religion so that it was less pagan, thus making it easier to convert the Norse people. As a result, much of Norse mythology is vague and incomplete. One example of this in the story is the exact difference between Valhalla and Folkvangr. We know there is a difference, but besides the ruler, Odin vs. Freya, it's not exactly clear what that is. Also, the whole concept of Hel as a place did not appear to exist until the Catholics came around. Likely, according to many historians, it was created by the Catholics so as to introduce the idea of there being an afterlife not centered on death as sea or in battle. Additionally, there is much uncertainty as to how a soul is separated into a specific realm, with many having overlapping lines as to who is eligible for each. With so much vagueness, I took significant creative liberty in the setting and details of both Valhalla and Folkvangr. It was because of so much lacking details that I avoided Folkvangr entirely and only tried to portray the entrance to Hel. All of that aside, Atticus is dissatisfied here and wants to keep his options open, as anyone who is buying their eternal retirement home would be wise to do! So, let's follow him to the steamy jungles of Central America and see what else Thanatos has in store for him!