Another little Otome Isekai Original concept:
After they each wrote a fictional story, the online-mutuals Belinda and Joe agree to be each other's beta-reader. However, their discussion of the books turns into a disaster, as it turns out they don't like the other's story and critizise it a lot, until it escalates into a fight. After that fight, they are on bad terms, say they never want to interact again and block each other.
On the next day (?) they awake isekaid into a world that is a crossover of both books - dressed as servants in an old mansion. A time-freeze-spell on that building got just lifted, as members of the noble family owning it returned, after the building has been abandoned for many decades, to live in the residence. The owners just assume that Joe and Belinda are servants who got accidentally magically conservated by the ancestors from the damage of time along with the mansion and just let them resume their work. They do that work, not clearing up the misunderstanding, as they have no other job or place to stay in that world. And these noble inhabitants are none other than Belinda's protagonist and her sister - and her boyfriend?! Who is none other than Joe's protagonist!
Belinda and Joe are absolutely horrified that their main characters Rosetta and Jason are in a fix romantic relationship. Their stories are supposed to be different! Belinda thinks that Rosetta should do so much better than being with Joe's arrogant, dull, stupid, average-looking and horny MC. She should be loved by several handsome, upstanding men and choose the best of those in the end! Meanwhile Joe thinks that Jason could do so much better than being with Belinda's annoying, silly, push-over, prude and embarassing MC. He should get a harem of cool and sexy ladies! But as it is, Rosetta and Jason are so blatantly in love with each other, that no one else tries to flirt with one of them. For their authors, that is wrong! Unacceptable! Disgusting! They have to fix this mistake, even if they have to work together to do so! And so Belinda and Joe become the villains of this love story, cooking up schemes to tear Rosetta and Jason apart.
Despite that: The couple's love is strong and prevails! And to make things worse, more crossover-ships set sail, as some other characters from the stories also find love! - Belinda and Joe have to wonder at the end, why this keeps happening. Their characters aren't meant for each other, so what pulls them together? Could it be something stemming from their creators? Aren't Belinda and Joe through all their bickering, conspiring and co-working feeling such an attraction, too!? Could it be that... these authors are somehow meant for each other!?
Plots of the original stories:
In Belinda's story, Rosetta, the second daughter of a baron, recalls her past life as stylist on her 18th birthday. She proceeds to utilize her skills from her past job to make people look more beautiful. This becomes a sucessful business and Rosetta becomes rich and popular. The story alternates between customers asking Rosetta for her service and suitors taking her on dates in hope of winning her over.
In Joe's story, Jason returns to the Magic Academy to retake the entrance exam. After failing it the first time, he trained and studied the whole summer and somehow becomes very overpowered during this training arc. (Belinda: "It is never explained, how he suddenly gets so strong - without any teacher, too!" Joe: "He's just super talented.") Jason flaunts a power at the exam, that would already qualify his graduation. After getting redirected to and passing the final exam, Jason is bored and becomes a magical knight, a swordmaster, an adventurer, a hero. He triumphantly defeats momsters and villains. He rises up the ranks, from commoner to Sir, Baron, Count, Duke, King and finally Emperor.
More characters from Belinda's story:
Rebecca: The Villainess. Rosetta's elder sister, who is jealous on the MC's success. She tries to sabotage her buisness and reputation and wants the Male Lead for herself. Because Rosetta is a doormat (that's how Joe phrases it, Belinda prefers the description "purely kind and forgiving"), she always lets her sister get away with a slap on the wrist when she uncovers her current evil scheme.
Ludmilla: The Final Boss. She has no ill intent towards anyone, but a severly disfigured face, that poses a big challenge for Rosetta to fix. She is also the Male Lead's little sister and Rosetta has to "fix" her to be worthy of the crown prince in his parent's eyes and get their approval to marry him.
Rafael: The Male Lead / Crown Prince. He is so beautiful and perfect, that there is nothing that Rosetta can improve about him. And he is nice and charming.
More characters from Joe's story:
Kevin: The Villain. He was the High Mage and renowned Magical Prodigy, before Jason took his position. He was a judge at the entrance exam, failed to see Jason's potential the first time and accused him of cheating the second time, because he just couldn't believe that he had improved so much. Kevin and Jason hate each other, Kevin is very jealous and tries to bully and inconvenience Jason often, but Jason always turns the tables and Kevin ends up humiliated. At the end, Kevin snaps and calls upon the darkest, most powerful magic to defeat Jason. He still fails and ends up dead.
Selenas: The King. Raised as a spare, the second son Selenas ascends the throne after his grandparents, parents and elder brother all get killed during a terrorist attack. He is paranoid and thinks that soon his family's enemies will try to kill him as well. Outside of the inner palace, he always wears an armour around his most vulnerable parts and a crown that also serves as helmet. Selenas is shy, undisciplined and unsure, with no self-confidence, struggling to make descisions and give orders. He is also a quite talented mage in theory (about on par with Kevin) but can hardly cast spells, as due to his weak resolve, his magic also only manifests weakly. After Jason saves him from a monster, Selenas passes his crown to his saviour, recognizing that unlike himself Jason would make a great ruler.
While Selenas' entire family is killed in his original story, in the crossover Rafael and Ludmilla are his younger siblings and they are still alive. On the other hand, while Rafael's and Ludmilla's parents are alive in their original story, they are dead in the crossover. This way, Rafael is still the crown prince as the younger brother of the king, who has no children. In the crossover, the three siblings are close and have a good familial bond. Selenas annoys his little siblings sometimes though by acting overprotective due to his strong fear of another attack on the remaing family members.