Spoilers : The Abandonned Empress

Spoilers : Allen and Carsein's futures

In second timeline, Tia realizes she should be more "open" with her feelings and she's not actually alone, there's so many people who support her and love her.

Don't forget she also thought her father was somewhat "unfeeling" but realized he risked his life and household to make her happy.

He begged Ruve to fake her death and let her live quietly in another country, showing how much he actually loved her.

Thus 2nd timeline (2TL) Tia shows her emotions more and Ruve, seeing Tia showing all these emotions and laughing with Karsein and Allen, realizes she is not unfeeling and cold.

In 2nd lifetime, Tia's will to escape her engagement to Ruve clashes with Duke Jenna's stories, and that's how Ruve discovers that Duke Jenna cannot be trusted. Which completely changes all of their fates.

Also, don't forget that Tia inheriting her household makes it impossible for her to become Empress (due to some rules and stuff), so how can Tia be power-hungry and out to manipulate him, Ruve, when she appears to want to break off the engagement?

Thus 2nd timeline (2TL) Ruve realizes a lot of what Zena said about Tia was a lie.

Oh, and BIG SPOILER ABOUT ALLEN, but Allen, despite being much more capable than his brother, is passed over in favor of his older brother.
Allen wants to inherit the household, thinking he is better than his brother, but the parents think it's unfair, since the oldest son is supposed to inherit.

Even though Allen is definitely better, the oldest son is capable still. Allen thinks this means his parents don't really love him and he gets driven to Zena's side as a spy.

Allen is a Yandere to the core. In western terms, I would go as far as call him a sadist and a psycopath. In his POV we discover how Allen fell in love with Tia because she has PTSD and is nearly mad with terror. He finds her trauma beautiful, and wants her madness and obsession to turn to him instead of her father.

Allen also is sociopathic and possessive of Tia. At one point, he considers killing her father, Keiran, because Keiran sees through Allen's true nature.

He offers a ribbon to Tia, and after she starts to be healthy again he thinks of strangling her with it, in order for her never to change and keep the memories of her looking only at him. He also kind of has an erot*c daydream about strangling Tia to death so she will always be his. His other plot is to kidnap Tia and keep her locked up in a secret house forever, so she will belong to him only.

There is the moment in the carriage when in the manhwa Allen kisses Tia's hand. In the novel he kisses her on the lips, while she's sleeping - so unconscious and very much unconsenting.
This moment gave off heavy creepy vibes. Allen also spent years building a house for Tia somewhere, and after she rejects him, he actually starts leading her out of her way home, planning to kidnap her and keep her locked in the house for the rest of her life.

He renounces his plans at the last minute. His POV is extremely disturbing. Lots of people actually felt filthy and frightened after reading it. At this point in the novel, I was quite happy to see Allendis disappear from Tia's life for good tbh.

(As an Allen fan in the beginning, it truly shocked me when I read it.)

Don't get me wrong, Allendis never did those horrible things, and he realised he was sick and left to protect Tia. He's not a villain. Yet, this is too much, and I really hope the manhwa doesn't insist too much on all these details for the sake of Allen's fans. I think it's enough to know he's Duke Jenna's ally and spy. I've seen the raws, so I know this will be portrayed in the manhwa. And I think it's largely enough to explain to the fans why Allendis can't end up with Tia.

However, he does have a moment of clarity where he realizes he is f**ked up in the head and he double-crosses Zena to the current Emperor, who sends Allen away to another country, but thanks him for realizing the error of his ways.

So Allen did love Tia enough to realize his love for her was messed up and psychotic.

For Allen's fans in the novel he realises his obsession for Tia is getting too dangerous and goes away to heal himself. Tia gives him a token with her initials and, with the flower embroidered on it, Allen sees it as a sign that Tia is still willing for him to be her knight even if she clearly rejected his love. So he vows to heal himself and come back. Carsein asks him to come back so that they may compete fair and square. The emperor also asks him to come back for his talents are needed. (Allen will only come back 13 years later.)

About Carsein, he is Tia's protector to the end. He's a very nice and reliable friend/brother to her. But sadly, his love is unrequited and he has to give up on it when Tia accepts Ruve's hand.

His own mother was Keirean's fiancee before Keirean fell in love with Jeremiah. And she was humiliated and heartbroken when the man she loved asked for the breaking of their engagement to marry a woman far behind her (and his) station.

To do that, Keirean swore the binding oath (an oath that requires his death if he breaks it) to the emperor, offering his unllimited support and loyalty to the crown in exchange for a wish. And emperor Mirkan who had been waiting for Keirean's surrender agrees to his wish and breaks his engagement to his sister (Carsein's mum).

So you see, there's a heavy history behind Carsein's innocent love.
Carsein ends up alone at the end of the novel. But in the collection of sides stories in volume 6, we learn that he's married (it is unlikely to be Lady Genoa, as she was engaged (and married?) to Alexis - Allen's brother.) He has a son called Gradis who is the playmate of Tia and Ruve's daughter Diana (Dia, who is her mother's replica with her silver hair and golden eyes).

Ah and concerning Carsein's future wife Princess Lynn(Princia) of Lua is dating his brother after he proposed to her in front of everybody, and they’ll get marry and have a son. So she is not Carsein’s wife. It's probably because she's called Lady of Ras that fans were confused. But she is only Carsein's sister in law. She becomes Tia's first real female friend btw (whitout political motives unlike the "friends" Tia met at the tea party and after that I think I remember she gets closer to Lady Genoa, but with her, the relationship is more because they understand each other).

If the manhwa follows the novel Allen will drop from the story quite soon and go far away, while Carsein will take the leading role. He friendzones himself by treating Tia like a little sister, yet there will be a real love triangle between the two of them and Ruve.

If you want to know more about that triangle : After Jieun appears and is Ruve's partner at a ball (she was forced on him), Carsein takes Tia to this ball and even gives her a red dress to match with him (giving a dress to a lady is equivalent to declaring one's feelings for the lady) -
For Carsein's fans, Carsein manages to kiss Tia on her forehead. But then ruins the moment by flipping her forehead with his fingers. -_-
I don't know if they will keep it in the manhwa as they cut Allen's kiss. But it's innocent enough so I bet they'll keep it. It's not long before he gives her the red dress and they go to the ball together. (Carsein did it with a political intent but Ruve doesn't know that and is very depressed.)

Yep, you read it correctly, Ruve is not jealous (angry-vicious) but desperate and quite chivalrous. He humbly asks Tia if she can leave him at least a little chance? (He already asked her several times to give him a chance). She says she's powerless to refuse his order. But he swears he will never take her by force. For there is no meaning for him if she is unwilling, he wants her heart, not to possess her, and for her to love him as a man, not a king. She says she can't accept him and he leaves with a broken heart. As for Ruve's reaction when Jieun arrives he clearly says to Tia : "In my heart there is only one person already (you), so there is not place for Jieun, nor for anyone else." Ruve definitely seems the gentleman, romantic, sweet type of lover.