"I'm sorry," Rylee began, "but it's not like I knew drawing the sword would lead to the citadel exploding!"
"About that," Sissy started, "what exactly happened?"
"We...have a lot to unpack," Seliph replied, before launching into an explanation of everything that went down while the two of them were outside the citadel.
"Oh, right, Rylee," Kalista broke in, "do you remember everything?"
"Of course, as far as I know I haven't forgotten anything," Rylee responded.
"But...but are you on our side?" Kalista continued.
"Why wouldn't I be?" Rylee asked.
"It's just...hard to tell, I guess," Kalista offered.
After a brief moment of quiet, Rylee then said, "We should probably go. That explosion will have drawn some attention towards us."
"Yeah," Seliph agreed, "we've got a long way back to Elturel. Do we know how much Zariel was delayed by when we sent our distraction?" Seliph then asked Olanthius.
"Can't say," he admitted, "but we don't have much time. Less than a day, for sure."
Travel back to Elturel took a few hours, but once the great city came into view, there was a much bigger problem at hand.
The city, formerly suspended hundreds of feet above the surface of Avernus, was now floating feet above the River Styx. Another few hours and it would be completely submerged, damning all within the city to a swift end, only to be brought back as devils in service to Zariel.
This was bad enough, but there was one more detail that came into view.
Legions of demons and devils were locked in a fierce battle surrounding the city, with Zariel, as Lulu observed, "right in the thickest, most dangerous part of the battle, like always."
In case that wasn't enough, the party caught sight of a nightmare flying down from the sky at breakneck speed, carrying a figure the party instantly recognized as Advocati.
The party all slowly turned to face Faust.
"What? It isn't as if the angels were offering us any better alternative."
Seliph rolled his eyes and pulled over, and the party climbed to the roof to speak with Advocati.
"Thank you for agreeing to meet me so quickly. I've been hard at work undermining Zariel, and I'm still absolutely thrilled you guys agreed to let me take over this place once Zariel is out of the picture. I can't begin to thank Faust and Sissy enough." Faust's quick shift between confusion and anger seemed to be the exact reaction Advocati was hoping for.
"Now now, I'm here to make things easy for you. Like I said, I've been undermining Zariel, and to do that I've spoken at length with a lot of her, shall we say, less enthusiastic soldiers, and they've agreed to step aside and let you through, but only if you show them this." He then flipped a red coin towards Faust.
A red soul coin.
Faust, trying to keep his cool, merely asked, "And whose soul is in this coin?"
Advocati chuckled, then responded, "What makes you think I know or care about that?"
"What's so special about this coin then?" Kalista demanded.
"Why, it's red. Show this to any fiends you run into in that field. The ones who are out of the loop will probably just ignore you, but the ones who are in the loop will specifically get out of your way. The demons...however..."
Rylee quickly responded, "The demons, however, will be no problem for us."
"Precisely. Love the confidence and the new look, Rylee," Advocati added with a wink.
"Don't think you're suddenly in my good graces. I could and still might end you without second thought."
This response was...not what the rest of the party was expecting, but Advocati just smiled. "Either way, I've done what I could. Now, go work your magic."
"Sincerely though, thank you," Rylee said. "We hope to end this now."
Advocati bade the party farewell, then mounted his nightmare and flew off. Where? I dunno, out of the plot for the rest of the story though.
With their goal in sight, the party slowly made their way through the battlefield towards Zariel's location, being interrupted a few times for direct combat or, in a few cases, avoiding magical explosions nearby.
At this point, Zariel was levitating above the battlefield, her attention drawn to what the party was up to. While three people in the party were capable of modest levitation or flight (some more than others), getting up there and maintaining that height could be difficult. To that end, Lulu finally transformed into her true, giant golden mammoth form, offering to lift those who were incapable of flight to Zariel's location.
As the party closed in on Zariel's location, Seliph shouted her name at the top of his lungs. She was watching the party close in on her, so it wasn't to get her attention. It was a show of defiance.
"Zariel," he repeated, once they were within a decent range to speak. "It's time to end this."
"You all came back. And...you brought Lulu, the sword, Olanthius. What's this all about?"
"Rylee," Lulu began, "present the sword to Zariel. That's the only way to break this."
Indeed, Rylee noticed that the sword seemed almost magnetically attracted to Zariel. Thus, she let it go, saying, "Come, Lady Zariel. This isn't the real you. You have a mission to fulfill. Let us leave this place. Come home."
Seliph added, "We know about what happened in Idyllglen. What happened afterwards. All of it. But we also know that you don't have to do this anymore."
The sword landed in Zariel's hand, and she began to scream in pain as the sword seemed to burn her on contact.
And as much as I want to say she pushed through the pain, let it change her back into her original form, and we all got the happy ending we wanted and worked so hard for, the truth is...I can't. Sometimes, you can do everything within your power in the most proper way you can find, and due to the agency of others, it just doesn't work. Sometimes, like in this case, the dice have other plans.
Snarling in pain, Zariel shouted, "With this final rite, I discharge my divine duty. Let my name be forever struck from the ledger of Mount Celestia." She then tightened her grip around the sword, crushing it.
"Now, I'll do the same to all of you fools who dared mock me!" Zariel shouted, readying herself for combat.
Seliph quickly leaned in close to Lulu's ear, saying, "Time for Plan B!" Even though neither one of them knew what Plan B was.
"Wait!" Rylee shouted. "Zariel, you made me a proposition. I serve you, you let my friends and the people of Elturel go. Is that still on the table?"
Zariel, taken aback, relaxed her stance and smirked. "Why, yes of course. I had wondered if you'd even remembered my proposition considering how quickly the five of you abandoned the one quest I gave you. It almost felt like our discussion didn't even happen. But yes, of course," she said, extending a hand. "My word is law. Agree to bow down and serve me, and your friends and Elturel can go back to the material plane."
"Rylee, stop!" Seliph began. "Don't do this!"
"Yes," Faust added, "you know this isn't going to work."
"Please," Rylee said, "it's the only way. Lulu, please take everyone to safety."
Lulu reacted in shock, asking, "Wait, who are all you people? What's going on?!"
You see, something terrible happens with Lulu if the party fails to persuade Zariel to turn, her mind breaks, and any number of trauma-related stuff can happen. Thankfully, she didn't faint, leading most of the party to fall to their deaths, but instead, her amnesia came back, and it came back strong.
"Don't worry, Lulu. I'll make sure you're safe. Just get everyone a decent distance away from here. Go!"
"Uhh, right!" Lulu then turned and shot in the direction of Elturel.
Seliph, however, was not taking this well. "RYLEE!!! IT'S NOT TOO LATE!"
Thing is, it was. Rylee took Zariel's extended hand, and could feel a fundamental change within her. That is, she became keenly aware of the pact her soul had just forged with Zariel, and her appearance began to shift to look more like Zariel, or, even more disturbingly, like the image of herself Rylee saw in the mirror not so long ago.
"ZARIEL! THIS ISN'T OVER! AS LONG AS I DRAW BREATH I'LL OPPOSE YOU AND YOUR ENTIRE DAMNED KINGDOM! I'LL BURN THIS ENTIRE PLACE TO THE GROUND IF I HAVE TO!"
Seliph's shouting eventually lost all coherency as he broke into sobs.
Eventually Lulu landed on one of the broken streets of Elturel, frantically asking the party what was going on, to which Seliph muttered, "We...we're nobody. It doesn't matter. None of this matters anymore."
High above Elturel, Zariel and Rylee floated towards the Companion (brief reminder, the thing that was meant to help with their vampire problem but ended up being the very thing that dragged the city into Hell in the first place). Once there, Zariel handed Rylee the hammer she had previously been using in combat, saying, "It only makes sense that this be your first act in service to me. Just hit the Companion, and all will be returned to 'normal.'"
Rylee looked down at the city of Elturel. She thought she saw her friends looking back up at her, but at that distance it could have been anyone. A tear rolled down her cheek as she said, "My beloved friends...I'm sorry." Without another word, she destroyed the Companion.