Spoiler(Trigger warning:S*icide/torture) : Firstly there are multiple times in the timeline when both of them die and regress:
1. Princess Yermondi slashes the Fl's neck causing her to lose her voice again. She jumps and dies and regresses just before the Ml's eyes at least a hundred times to get her voice back. This drives the Ml to almost madness and his redemption begins from this book(vol 5) As someone said the FL's family had come to take her back but the ML opposed vehemently.
2. The FL went to the basement again to use dark magic to reverse time. Time didn't reverse, but her voice healed a little (it stick cracks and is painful tho) and she got her memories back about the first timeline (in which Carlotian killed her)
3. She starts loving Carlotian again. As soon as readers think things are healing!!!boom!!! Plot twist. On the day of the banquet she realizes she has ptsd from Carlotian killing her and she cannot touch Carlotian. This phase drives Carlotian utterly crazy.
4. Now comes Seth Doloranze{a marquis who had left his partner Dorothy (Dorothea's friend) because he's obsessed with making Areadeline love him like she loves Carlotian} He had requested the emperor to help him obtain Areadeline.
5. The emperor (if you haven't expected already here it is) is the last boss. The actual one who had made a contract with the devil and pushed Yermondi to do the same. The reason? He's obsessed with the fact that his brother can love and he can't. Hence, he wants to destroy anything his brother loves from his childhood pet to his wife. His brother, is the late Duke Denaves Or Carlotian's father who killed his own wife due to the madness caused by detrosea(Carlotian's sword).
6. A little context here for manhwa readers. Areadeline goes into Carlotian's room to get killed by him early on(when she decided she doesn't want to trouble the servants anymore). Carlotian chokes her because of his madness just like his father had choked his mother. This madness is caused by the demonic energy of detrosea at night. They both regress in time. Ariadeline's voice suddenly heals and the detrosea's madness is transferred to her. While managing her during her madness at night is when Carlotian slowly comes to love her. Ariadeline and him both search for the holy relic at a temple at Anrize and Ariadeline swallows it, making her a saintess.
7. So now coming back, the emperor instead brainwashes Seth to kidnap Ariadeline and bring her to him. Seth does so. But the emperor still sends seth's cut off head to Carlotian asking him to come so that he can hold him hostage. Carlotian does so and both the MC's are taken in a prison where the emperor's attendant repeatedly slashes, cuts Arideline(even impaling her eyes) and asks her to sing continuously to heal herself.
8. When the attendant leaves Ariadeline is half dead and asks Carlotian to kill her so that they can regress again. But she doesn't regress this time. Nor does Carlotian. So Carlotian goes crazy returning to the mansion.... Holding her dead body for days (even washing, feeding her) Then he goes totally wild and reaches the castle, kills everyone including the emperor and kills himself.
9. If you're hoping for the story to end now, hold my beer because this ain't the end. They get revived. AGAIN. This time Carlotian encaptures Seth, tortures and kills him. He sends Seth's head to the Emperor. The emperor realizes that he has understood his plan and goes ultra pro mode on dark magic building a black dome engulfing the castle and the church.
10. The emperor actually wants his brother's bloodline to be totally wiped out. And ohh, after regressing this time, seeing how far Carlotian can sacrifice for her, the FL's ptsd is magically gone It's now Carlotian who stays away,because he doesn't want the FL to have seizures again. Now ultimately the emperor has to be killed. Carlotian and Areadeline take way too much time here to torture the emperor who's been consumed by the devil. So much time, that Carlotian, himself gets consumed by the devil.
11. To put evil to an end and establish righteousness, Carlotian stabs himself to kill the devil with him. Bro dies, AGAIN.
12. And as you can expect, God somehow replenishes his HP and he is revived. AGAIN. At this point Carlotian has memories of his first life and how he killed Areadeline. The moment he revives is the moment when Ariadeline is about to s*icide again, cuz Carlotian is no longer alive. Carlotian stops her and both have a happy and spicy ever ending afterwords
13. We can also see Carlotian realizing that he never truly "loved" Dorothea (expected). In another side story we also see the MC remaining the same and throwing a childish tantrum assuming that Carlotian was having an affair with Dorothy.
*The End*
Girllll I don't know who to simp for ╥﹏╥ they're both GODLY majestic it's not even healthy for my heart anymore ahhhhh imma just die at this point