Cersei

»I will not marry him. I will not.«

»Oh, you will.«

Tywin Lannister's voice was calm, but sharp and without hesitation. He wouldn't give her any chance to change her fate, that much was clear. The way he sat directly opposite her, graceful and upright, combined with his piercing look sent cold shivers up and down her spine.

»Don't make me do this, father. Not again. You shipped me over to Robert Baratheon a long time ago. I don't want this marriage.«

»Go on, then.« Tywin tilted his head a little. »Speak. What do you want.«

Cersei held her breath for a split second. Was her father, Tywin Lannister, Lion of the Rock and Warden of the West really asking her what she wanted? »I want to stay here - with Joffrey. With Tommen. I will not leave my children.«

Tywin looked her right into the eyes. »Don't be a fool. You're a young - still young - fertile and rich woman with a powerful name. No matter what, I would have arranged another marriage for you either way. Oberyn Martell is a skilled, open-minded warrior from a region where men and women are considered equal. And a marriage with him implies that you get the chance to be with your daughter again. That is more than you could ever wish for.«

Cersei had to swallow. She hadn't seen Myrcella in months and was already missing her terribly. Her little lioness, her perfect girl... »The Martells despise us, especially Oberyn. Why should he agree to marry the daughter of the man that he thinks murdered his sister.«

»Because I have promised him something in return that will soothe him.«

Cersei raised an eyebrow. »And what 'something' are we talking about?«

»Something that is not your concern. You will learn it soon enough.« Looking down at his letters, her father showed Cersei that the matter was closed. Well, not for her.

»I am the Queen. Father, please. My place is here, in Kingslanding.«

Tywin didn't bother to look up. »You are Queen Regent and very soon you will be nothing more than Queen Mother and Dowager Queen. At Oberyn Martell's side, your title is going to be Princess of Dorne. Not Queen, but close enough for you.«

Without another word, the golden lioness stood up and made her way to the door. She knew perfectly well that her father wasn't a man to argue with, so she had to accept this betrothal. At least for now.
Before she could open the door, Tywin raised his voice again without stopping looking at his letters. »Maybe you'll even be happy with him.«

Cersei stopped herself from snorting and walked out of the chamber. Happy - with a viper. Of course.

Oberyn

»I won't marry her. No. Never.« Oberyn shook his head in disbelief. How could his brother make such a proposition? As if he didn't know him at all.

Doran Martell sighed and looked at the Water Gardens. The view was incredibly beautiful. Flowers blooming in various colors and forms lined the paths. »At least consider it.«

»Why should I?«

»Because I am sick, brother.« Doran's expression was dead serious, as always. Not only because he was in constant pain.

»That much I know. The rich man's disease, that's what they call it.« Oberyn had heard the servants talk about it more than once.

»Sicker than you might think.«

Oberyn took a deep breath as the Dornish sun burned down at him. It was a hot day, almost too hot, even for a Dornishman.

»Ellaria would never-«

»Ellaria is your mistress, not your wife.« Doran's voice became more and more reedy.

»Paramour«, Oberyn corrected him. He preferred the term over 'mistress'. It sounded much more... Passionate. A passionate word for a passionate woman.

»Whatever you would like to call it. Truth is, she is not fit for a marriage to the next ruler of Dorne«, Doran said, leaning back in his chair.

»Sicker than I might think, the next ruler of Dorne... What are you talking about? Trystane is already married to Myrcella and by law he will be the next ruler of Dorne after your death.«

»I am talking about your future.« By now, you could tell that every word meant a huge effort for the Prince of Dorne. »Trystane cannot father children and my time is coming to an end. Therefore, I am going to name you my heir.«

In fact, Oberyn had observed the Maester visiting Doran more than he used to, but didn't think much about it. But how could this be? »How do you know Trystane can't have children? Did you see it in his eyes? Or observe his dick?«

Doran either didn't seem to notice his joke - or didn't want to. »The Maester told me. That is why your role is unbelievably important right now. The past will never be forgotten, but the future is yet in our hands. Cersei Lannister is not responsible for her father's or the Mountain's actions and an alliance with the Lannisters would strengthen our house greatly. And it was mother's wish. Don't you remember? She wanted you to marry Cersei. We would honor her with this.«

As much as he hated to admit it, but there was truth in his words. Oberyn didn't believe in the guilt of the younger Lannisters either and remembered his mother's wish very well. Nevertheless, Doran still hadn't convinced him. But before he could say anything, Doran went on talking.

»I know that you have no interest in strengthening the Lannisters, but I do know you have an interest in avenging our sister. Vengeance, that is your desire. And it always has been. If you marry Cersei, you will get it.«

Oberyn snorted, followed by a small, bitter laugh. »And how, precisely?«

»Tywin Lannister will hand over the Mountain to you and you can kill him in whichever way you want. Do to him whatever you please.« The Prince of Dorne reached for his brother's hand and took it. »If not for me, do it for the good of Dorne. For our mother. For our sister.«

The Red Viper let out a heavy sigh.
»Alright. I will consider it.«

I can't believe it. Game of Thrones has come to an end. But we still have fanfictions, don't we?
I have always liked this pairing and their chemistry, but there aren't many Cersei/Oberyn fanfictions out there, so here we go. This will definitely take time, but I'm pretty sure that it will be Cersei/Oberyn endgame.
Due to English not being my mother tongue (I'm currently learning it and try to improve my skills by writing fanfictions), there may be some errors.
Sit back and enjoy the ride!