[Suzerain of Sheol]

That wasn't actually a question, Illusion....

Nonetheless.

First, Zephyr and Fenrir have been lovers since the Taskal War. I'm not sure how that caught you off-guard.

And Ari, that's not entirely true, though I honestly hate talking in terms of "good" and "evil" since they're incredibly simplistic. Falla and Faust have both been tremendous traumatized by what Ryuko's put them through, and have been fundamentally changed as a result. Even if Ryuko's hold over Faust were to be broken, he would be a very changed person for it; the possession has infected his very sense of identity on the most basic level, and that's never really going away. Falla has become bitter, hopeless, and in many ways merciless because she has been pushed beyond every extremity. It has nothing to do with the curse on her, in that sense; she's just become willing to do anything at this point to bring Ryuko down and save Faust. It's hard to call either of them "good guys" at this point.

Beyond that, I'm not sure what was so confusing about the event story. The Nox Nocturnalis is obviously going on, Pandora is holding a massive celebration in Isremme (the capitol city of Quesaria). She has a tender, hopeful moment with Feysha in the royal gardens early on.

Falla tries to summon the souls of the dead from the last year to Toamna, but the curse on her prevents the magic from working and instead tears down the spirit-gates to Toamna. She loses all hope and drags Niya's soul out from the legions of the dead, meaning to use it against Ryuko. So, she sets off to Quesaria with Niya in tow to try and get help from Pandora, since she's kind of helpless on her own, as we've seen. She knows that her curse will ruin anyone she comes near, but she's beyond desperate at this point.

Faust has been left alone in Ryuko's empty kingdom on Quesaria, while Ryuko has been off dealing with stuff on Deivai for the past several events. As the Nox begins, he goes out in a twisted mockery of his old purpose and reaps the souls of the dead on Quesaria, enslaving them as Ryuko has enslaved him, to populate Ryuko's realm as a gift to his master. Afterward, he continues his quest to try and open the gates to the Corrupt Realm for Ryuko and summons the spirit of Braen from the void. Death has driven Braen mad, and Faust can get nothing out of him, so he enslaves him as well, believing that Ryuko will be able to open the way through him, since he was the former god of the Corrupt.

That leaves Mirothea, who is the savior Dacorum saw in the vision Fenrir gave him. If Fenrir's role is confusing you, after she was killed by Braen during the Fight for Freedom, Lunae scooped her up from the void and reconstituted her in the Sentinel realm and began training/empowered her to be a new Sentinel. After that, Lunae fell into an unwakeable slumber of prophecy, foreseeing everything that was to come, her last act to pass the visions onto Fenrir, who was now the chief acting Sentinel. Due to the Sentinel's mandate to maintain the cosmic balance, Fenrir could only pass the vision to Dacorum, her most trusted ally from before, and hope that the prophecy would come true.

Enter Mirothea, chosen by Lunae, or perhaps by fate, to inherit the crown of Divinity and take Fenrir's place, as well to stand against Ryuko's darkness. As far as any of them know, she's the only hope of stopping him. So, Dacorum goes to collect her for her destiny, only to find that her parents are rather disagreeable about him taking their daughter away. They work it out, though, and they start off on their journey. Dacorum unfortunately didn't get any specifics with the vision, so he's rather at a loss for what to do, so he decides to bring her to see Pandora, hoping to both find news of what's been going on in the royal court, and to get a safe haven where Mira can be trained for what she needs to do.

...and that should just about cover it.


Edit: Oh, right, Fenrir and Zephyr. Fenrir sees that Ryuko is about to gain access to the Corrupt realm, which is where Zephyr has been living, and she can't bear the thought of Ryuko enslaving her, so she steps in and brings Zephyr up to the Sentinel realm to rest and heal in a crystal tomb, believing that she has truly suffered enough at this point. It's a minor violation of her role as a Sentinel, Fenrir is still very invested in her personal emotions, unlike the more dispassionate Lunae.