"I am 18 and all participants and characters must be 18 "

This going to be a slow burn RP so only so only for people with patience.

Basic plot.

My father is the king of a small but wealthy and strong country, living peacefully with his only son a young man fierce warrior and loved by the people of the town and respected among the soldiers, his wife is a beautiful woman coming from a royal lineage she is confident and holds deep knowledge of kingdom politics. There is a custom in which the King till the time he is on the throne has to put everything on line once a year where anyone can challenge him to a duel and if the king fails he dies and his kingdom is gone to the winner, not just his kingdom but his wife will have to marry the winner. Of course, for a long time, it was just a mere ceremony even if there was a challenge it was too weak, but not this time as the king was challenged by a strong brutal warrior although he was about the same age as my father he was able to get the better hand in the duel and kill my father.

Now my mother has two choices she can marry the new brutal king or she can prepare her son for the battle to take back the kingdom as a known politician she knows that the new king cannot ignore a call from the Young prince as the prince is popular in rank and people king will face mutiny and humiliation if he doesn't accept the duel. but if his son wins the duel the only way she can remain, queen, is to marry him, what will she choose morality or royalty?

there can be different scenarios in which this can be played.

a ) Mother will marry the new king to give time for her son to prepare for the battle in the meantime she will start people and ministers turning against the new king.

b) Mother and son run away into deep forests to survive there and return after a year to challenge the king

c) most interesting - After my father died instead of weeping mother started kissing the new king and it revealed that the new king is her cousin and they both have made this plan to kill my father and me but before I can be killed I was able to escape by the help of some loyal. During my time in exile, I fall for a girl but one day that girl was killed by you in a battle and after I defeat cousin your new husband I killed him in front of you so now we hate each other but as the custom, you have to marry me to be the queen. In any of the scenarios, the mother will have to marry her son to remain a queen and enjoy power.