*Medici and her two vampire lovers.*

"Guys, this is Isabella" Sarah introduced me,

"Okay guys so Isabella is apparently a first year, and from a random orphanage and didn't even know that her Dom is a king" Sarah laughed to me.

"You're with Edward? I couldn't handle him" Payton said. 

"Handle him?" I asked, the girls all giggled. 

"I didn't even make it past his manners phase" Sarah told me. 

"Edward shares the throne of England and Russian territory with his father" Veronica explained to me, 

"Wait what, England and Russia? What do you mean, England has a queen?" I told them, 

"Not the human queen silly, the Vampi-" Payton was cut off by Edward strictly calling my name. 

I turned around, terrified,

"Isabella, come here" he called to me, and beckoned for me to come to him. I walked over to him shyly, feeling the glare of jealously on the back of my neck. 

"Yes sir?" I asked him when I approached, he sat in between other doms. 

"Sit here darling" he told me and motioned to his lap. My cheeks were bright red, 

"On-on your lap Edward?" I asked him. 

"How DARE you address him by his name-" another dominant said to me, Edward help up his hand to silence him. 

"Sweetheart, I know you're still new to this, but you will address me as 'sir' or 'master' here. Now sit on my lap" he told me. I sat on his lap.

Edward whispered something to Eros, 

"Punish the girls for the gossip" he said calmly.

"Girls" Eros said harshly, they all looked over 

"You all are being punished together for talking about things that are not yours to tell" Edward said calmly. They all look mortified.

"Go wait in the red room, I'll be watching your punishment with my sub" he said calmly.

Arkhaios is a very secret society. Isabella, however, as a human girl was invited. No one knows that Isabella is a pureblood royal child. 
"Why would a royal child be orphaned?" someone would asked. Purebloods were rare, powerful, and honored. Royal families rarely concieved.
Because she's a Medici.
The Medici's, the thirteenth royal family. Previously the most powerful royal vampire family, until the twelve Royal famlies voted to have their line ended for war crimes.

Isabella is orphaned at birth.  She gains admission into prestigious academy outside of London.  When she attends the academy, she meets Edward.  
Edward is commissioned by his father and the headmaster to mentor and protect her.  While Edward is annoyed with the task, he falls in love with her.  Isabella learns that she is not an orphan, but in fact a very powerful, yet-to-shift vampire.  Attacks begin on her life.  
Damien, Edward's half brother was hired by Edward to protect her full-time at the Academy.  Isabella and Damien fall in love.  
The three are told their relationship is untraditional and forced to keep it a secret...
It won't be a secret as you guess.