The lovely devil (Yandere Sinbad x reader)

 Cedric (Last Name) was born into a family of simple villagers and was raised in a household filled with love... however love couldn't provide the family with what they needed and so Cedric began working for nobles at the age of thirteen. 

He soon came into contact with people so horrible and sickening that dark thoughts began clouding his mind and a desire to kill arised as he saw them abuse their power and harm others just because they had nothing better to do. 

Cedric being a very good looking man received attention from women both simple and high ranking but because of his beliefs he pushed everyone aside. 

One female however was not willing to give up, her name was Irina and she wanted Cedric for herself, her father belonged to the court of King David and so she asked him to arrange everything.

 A few days later, Cedric's parents died and left him and his three younger siblings to the mercy of the world, Cedric had two brothers and one sister who he treasured most. For their sake he began learning magic as he worked day and night to provide his siblings.... however because of Irina and her father he would be fired in a week or two... it was then that he began learning about the darkness and its might.

He would search for dark sorcerers with minor abillities and force them to teach him all they knew... soon enough he began using dark magic with ease and even created demons and beings of darkness from his own bitterness and pain.  His siblings were later taught by him the arts of darkness and before long they formed a small team of extremely capable sorcerers... Cedric indulged himself in darkness but never lost his goal in life, with his new powers he created a castle for him and his family and with a snap of his fingers he could now provide everything they ever desired. 

Months went by and Cedric grew stronger and stronger and along with his power his good looks also improved, that made every woman he came across attempt to earn his attention with Irina on top, still not willing to let him go. She eventually decided to go to extremes when she kidnapped Cedric's only sister, (Name) and used as bait her so that Cedric would marry her... it was on that very same day he learnt his parents died because of her... and he didn't hesitate to kill her in cold blood along with her father. 

That was a mistake as it drew the attention of King David.

The castle Cedric and his family lived in was filled with secret passages and traps that they had all created and they spent almost everyday hidden behind it's walls... the only outsider who ever came and left from there alive was King David who confronted Cedric and offered him a place at his court which Cedric refused... his brothers were weary of the king and so they kept (Name) away from the public eye... however that all came to an end when the king invited all of them to a banquet to celebrate his birthday... David took one look at (Name) before he decided that she would be his. 

Gifts, invitations to all kinds of activities... he did everything but was pushed away by Cedric who was seeing a very familiar pattern in all that.

(Name) as an individual cared only for her family and had grown to believe that there was nothing and no one, other than her brothers that could understand her, thus she rejected the king on multiple occasions and kept herself away more than any time in the past which irritated everyone in both sides. 

When one time Cedric challenged David to a fight for his sisters hand, David was defeated but was still unwilling to give up and hosted another match this time with Solomon as Cedric's opponent, it was the first time Cedric tasted defeat and despite Solomon's best attempts to make friends, Cedric refused and vowed to one day kill them both... a vow he was unable to keep. 

David kept pursuing (Name) and one night... he got her, he forced himself on her and then declaired that he would marry her the very next day... (Name) being desperate and not thinking straight committed suicide leaving only a letter for her brothers where she asked them to make sure that their bloodline wouldn't end with them... she asked them to find true love and not act the same way David did... despite their bitterness and anger the brothers did as their sister's letter asked and they were able to create families. 

David whose heart was broken saw that as trechary and attempted to destroy them... which resulted in Cedric sealing the castle away in a dimension of darkness where they spent the rest of their lives... for centuries the members of the family would leave the castle to seek out love, reveal their family's past and desires and then return to the castle where dark magic flourished.

And that was basically what the books you were reading said about this matter.

"I can see now why my father and uncles were dead set on killing Sinbad." You mumbled after you were done reading the book you had discovered in the library, it was the first of twenty four tomes of your family's history. The fact that you resembled Cedric's only sister now made you even more scared regarding Sinbad's and David's co-existence.

"That's not all dear, the book tells you a lot about Cedric but only his spirit can really tell you everything." Your grandmother advised and you sighed... it was true but you still had twenty three tomes to read and you could already imagine how exhausting that would be.

"Maybe you can tell me a few things Grandma... about our family."

"Well, I can start with my grandfather, a stern and cold man who would kill anyone mercilessly... he only cared about our family and wanted to ensure that our dominance was known and our might remained unquestionable. That trait was passed down to my father and during his early teenage years he went so far as to experiment on people... they were horrible and unpredictable experiments that went so far as to test a person's  mental endurance before a demon completely devoured their soul while projecting horryfying scenes and bringing out desires so sickening it makes me shiver to this day." She explained and you gulped.

"Anything else?"

"I had an aunt... she was two years younger than my father but her magic was superior to his... she was forced to marry a king in a faraway land before she killed him, she was already pregnant and so she took control of the kingdom before she used all of its people as food for her shadow guards, only children and pregnant women were spared but the fate that awaited them was much worse."

"What do you mean?"

"Those creatures that devoured Gyokuen's soul and Arba.... it was them.... the women who later on were transformed into beings of darkness and became eternal slaves of this family."

"And the children?!" You asked horrified.

"At first they were just slaves. When they grew up however, they managed to kill her and the kingdom was rebuilt, her only daughter was sent here and thankfully she turned out to be far better than my father and her mother." She went on and you closed your eyes, you had been merciless, you had killed, destroyed and cursed people... but something inside you told you that you weren't nearly as wicked and evil as some of the members of your family were when they were alive.

"Her spirit... does she exist in Cedric's laboratory along with him?" You asked and your grandmother shook her head.

"When she died the women she had turned into monsters ate her soul as revenge." She said and you sighed... this was only a fragment of your family's history... you still had to uncover more, pleasant or not you wanted more answers regarding the history of this family.