Ragnarok

Ragnarok, act III, consists out of 4 sessions.

Part 1: War

Over the last few days, weeks even, the world has been getting darker. But lately, everybody has been hoping the sun will rise in the morning. The nights get longer, darker, colder. You have been preparing, but supplies won't last. The news has been slowly funneling in, the nations have started warring for resources, the towns have started warring for food.
Wednesday has gathered everyone, pacing and giggling slightly he turns very serious.
"Memory loss is a part of death. You are all here because you died a noble death, fighting your greatest enemy. I am honored to have known you."
A horn blares loudly, as if you're in a surround setup as you hear the rumbling of an army approach.

A big battle bursts out, the Valkyries and Jotnar fight, all the second characters should die (epically) by the hand of Kiruko.
The Jotnar are led by Garm, who will kill Tuesday before the battle ends.
Upon defeating Kiruko and the leader of the Jotnar (Garm), the giants will skatter. Leaving the ruins and remains of the battle.
Sol and Mani will cry for help as Mani gets eaten by a large wolf and sol has a dark hole inside hers, almost as if her shadow is eating her inside out. Behind both of them stands Sana'var'el Guath in her kobold body.
Frey teleports in with the key part and asks the adventurers for the shard. When they can't present any, he instead asks which capital they whish to get it from, and teleports everyone there.

Part 2: Locked

The world shakes, in darkness.
Chains break, the great wolf of fenrir is freed. Running from the total twilight to the center of the world.
Next to Axa, the ocean village, we see the ocean recede. The water level plummets as the shoreline moves over a kilometer further away, the great world serpent surfaces as the ocean life perishes.
The mountains crack as a great dragon splits it, leaving a big cavern between them. We see the horned dead of helheim march, towards the world tree.
The dark elves pray, to their pale mistress. Her black crown flashes with ice, as we see all throughout Svartalfheim, the dead rise from the grounds. And march towards Baldr's Gate.
And, lastly, we see the Jotnar army, beating their shields with the shaking of the ground. Their volcano erupts. As we see Loki, pull a sword from a rock. Raising Asaruludu up to the sky, the fire giant, Surtr gets freed from the blade and lets out a belting roar.

Nessus

Frey barges open the door to Hel's Castle. Leading the adventurers into the silver mist at the entrance, he will pull the entire castle and fight of the fiends, while they fight Hel.
The lady Hel Person wields a staff with a shard of the bifrost as it's crystal. She is immune to all damage as long as she wields that staff. (statblock) She will continuously spawn new fiends (statblock).

Svartaflborg

Frey opens the door to the night castle. He will hold back all of the undead as the party converses with the pale mistress.
The pale mistress has the adventurers fight a challenge. And afterwards she asks them what her name is.

Alfborg

Filavandrel will monologue over how the light was first owned by the elves before it was stolen by the Aesir. Why should the adventurers have it? They couldn't be bothered to go through their favour system.
They will fight him and his elven servants. In his throne room, lit by a opalescant skylight. This light heals all his wounds every round of combat.

Part 3: The Choice

The wall lies destroyed, Baldr's gate a battlefield yet to bury their dead. The only thing coming above the silence are the echoes of a past, softly wispering "Welcome to the Rosewood inn, where you're always welcome. And always home."
You venture down to the Rosewood tomb, past all of the surviving civilians, Aesir and Vanir. You cross Vidar on his way out, he mutters some words at you. ("I hope you're meddling is beneficial" in draconic) Before making his way outside to fight the wolf.
Opening the hallway to the great door down in the tomb, you are met with a surprising view. A handsome, strapping tall dark man. With glistening muscles... lies on the floor in front of the door, a shattered golden horn at his left side, a gleaming but broken sword at his right.

The dagger is the same one Blue was stabbed with (Loki's). After entering the key and turning the lock, the roots will retract. Showing the lowest layer of QUEST: The World Tomb. In it are various tombs, many with old forgotten names.

There's a large atrium in the center. A gigantic paned glass window of a tree that is connected to everything, a large battle surrounds it, with a big feathered dragon gnawing at its roots. In the atrium, there's a stone bed, with platinum manacles. In it, the dead body of Loki, limp with his hand dramatically hanging of the table. Floating above him is a figure, clad in shadows. Tattered in streaks of cloth made from darkness. With only a faint skull visible underneath their shadowed hood. "Well done my trusty warlock, you have finally set me free." From behind him a small ghost girl peeks out and points towards you, Powder. "It was her who hit me, dad."

Behind the big stained glass window is Ygdrassil, the world tree. Mimir is bound to it and is sleeping soundly. In front of him is a little pool, a well, of water. He will complain a lot about being tired, and tell them to take his head to friday.

Part 4: The Beginning

The world has shook many times over, each time bigger than the last and each time you thought: "It can't get any worse than this." This time, it crumbles. The ground falls away into the darkness of the void, the walls that held you somewhat safely have dissappeared, the houses that characterized Baldr's Gate have dissappeared, the Rosewood Inn has dissappeared. Instead there is a valley, wider than Baldr's gate got to be. In it are the remains of an ancient village sticking out the floor, central to all is a large temple that you are inside of right now. Out of the temple sprouts a giant ash tree, it's roots eminating from the side and spreading around through the ground. The tempe has 2 towers, one you know as the entrance the the rosewood tomb, the other is the door underneath the staircase of the rosewood Inn, only the tower reaching up to that door is actually the tip of the great Ygradrassil tree.
Before we continue with what's about to happen. We'll pan the camera over south, here we see the great Jormungandr crawl on land, it felling an emerald dragon with a single bite, before meeting his destined enemy, Thursday. The pair meet eye-to-eye as Thursday grabs his axe, he jumps and swings at the great serpent but as his axe meets the thick hide of the beast, it's head breaks clean off and Thursday ricochets off. With this, the battle is shortlived as not long after Thursday falls to the poisonous bite of the world-serpent. Who continues raging on the elven kingdom, starting with the coast cities.
A little bit more north, Vidar, now in his true shape of a crystal greatwyrm, meets the wolf Fenrir in a deadly battle. The two bite and claw at each other but the battle has no winner as they both fall to fatal wounds after a lengthy fight.
So we circle back to the world tomb, next to Mimir's well. You know who's coming, what do you do?

After a little while, Surtr will show up, this will be announced by Freyja's Death. The armies of the dead, the undead, the valkyries, and even the nivix show up to fight at ygdrassil.
Using the statblock of a Terrasque, Surtr will only start taking damage after being hit by a fragment of destruction or an Aesir weapon. This resets if he has not been hit for a full round succesfully. Friday will join the battle (initiative 0) and heal anybody that asks with heal. She will die on round 6.
The end:

Just when Surtr is at his knees, about to fall to the heroes' damage. He plummets his sword into the world tree, setting the entire world aflame. You unleash your final blasts, throwing everything you have left at him. Killing him in the process. The lava spews forwards from his body. As the entire flaming world sinks into the ocean, you expect a flaming death, or a drowned death. But instead you don't feel anything, you don't even see your body or your friends anymore. Instead you all see the world from above, from an outsiders view. As everything you've known gets destroyed.
But... after some time, 2 crows fly across the ocean, which slowly retreats to show a new land. In it's center, a small ash tree sprout. With a small wellspring next to it. And a voice, one you all feel like you've been hearing your entire time here, goes: "Well, I guess that's it. I hope you enjoyed the story. You were all magnificent. You almost had me this time. Again?" As they bow, in front of you.