To clarify, actress Margot Robbie is the face claim here, though the character is not at all the same as the actress. Instead she’s a Queen.

This rp involves some aspects of body worship. It involves him kissing and sucking on her nose, thighs, face, hair etc, and her using her elbows, feet, and even hair to get him off or rub outside his crotch.
There will be lots of him cumming in his boxers, exploring her body with his mouth, her using her feet, elbows etc on his crotch, and just generally him worshipping her legs, thighs, pussy and face.

Queen Margot is Jack’s Aunt. The royal dynasty is obsessed with keeping things in the family.  
Margot is the ruler, but she’s also seen as the most gorgeous Woman in the world, the closest thing to a Goddess.
At the same time, she’s madly in love with her nephew and sees him as her partner.
In reality she’s a really tyrannical and evil leader, like a real modern Cleopatra type, extremely intelligent. But to Jack, she’s lovely. Apart from the arguments and disagreements they may have, they love eachother deeply.

He is completely sheltered from the reality of her rule. He’s grown up in the family household and sees her as the most perfect ruler, one he could never disobey or think of badly.

I’d like to make it our own so I’d like if nothing sexual had happened yet when we start, but they can already be very close. And since she’s intelligent she can have set things up so that she can move into using him sexually very easily, without any complications (that way we don’t have to waste too much time) He trusts her completely of course, maybe she’s even set him up so he is staying in her master bed, waiting for her to come back after a long day.

He’s her favourite obviously, that’s why she’s moved his quarters to her bedroom.
She loves being worshipped and sees it as charity that he gets to worship her
She loves him and maybe vents to him on the odd day when somethings bothering her. Jack sees the side of her no one else will ever see.
At the point where we start Jack is a virgin, which makes her very protective of him and his virginity, because the whole family are sort of into him and other female family members eye him. Margot makes sure female members don’t get to spend much time with him. 
Margot has a sadistic hatred for Jack’s older sister, princess Emma.
And she decided to make it a rule that Emma isn't allowed a partner
Mainly because she finds it hilarious and it makes her feel powerful. Sometimes she is horrible to Emma and Jack has to always be on Margot's side.
Margot can be anywhere 30-75 years old. A special oil is applied to her body each morning that only she has access to, which keeps her looking and feeling youthful, like she’s in her mid 30s as in the reference photo. And there’s also rumours swirling about her possible immortality.

[M4F] Play as Queen Margot, modern day Cleopatra, ruler of a dynasty obsessed with incest, and madly in love with your own nephew, who you’re protective of! You are a tyrant to your people, but he thinks you’re perfect! (prompt below!)