Demon king

[T_B]

I'm 17 years old with my birthday coming soon some things about me I have black hair like my mom I try to stay in shape and the weirdest thing about me is that I have red eyes 

Ny mom either cheated on her husband or was raped when she had me because I looked nothing like him my sister is 19 years old and has his green eyes and blonde hair we believe she cheated on him because they don't sleep in the same room 

On my 18th birthday some portal opened and a beautiful woman came through she said that she couldn't believe that my mom kept me a secret from her I was distracted from what she was saying before her outfit left little to the imagination and her D cup breasts looked like they was going to pop out

She noticed where I was looking and took her outfit touched my dick and said do you want to fuck me son I told her yes afterwards she told me that she was a succubus and 18 years ago she seduced my mom and impregnated her with me she also told me that a succubus could get pregnant or impregnate a woman with a succubus baby how ever once in a while a incubus is born to rule over the demons and the last king was around 3000 years

Not long after she told me that my mom walked in to wish me a happy birthday when she saw the succubus she freaked out and tried to keep her away from me she told my mom that if I was born an succubus I could have stayed but because I was born an incubus I had a destiny to fulfill and she can't keep me from it she told me that I have 1 week before she'll come and take me if I want a human wife or lover to have them in this room with me and marked when she gets back

Mom told me and my sister (she overheard mom freaking out and heard everything) on how one of friends convinced her to go out drinking and at the bar she met the succubus and was took to a nice hotel room and was about to cheat for the first and the only time and it was with another woman as they were having lesbian sex she was asked if it was ok to stick it in mom thought she was taking about a strapon until she felt cum inside her

A few days later my sister told me that she doesn't want me to leave her and asked if she can become my lover and she helped me find a way to make mom again to become my wife 

The mark shows that someone is a wife or lover and is unavailable unless the mark giver ok it succubi don't really use it unless it's for love because succubi are demons of love and lust if the mark is used on a human it will stop their aging at 18 the same age succubi stop aging if they are past 18 their bodies deage back to 18 and change their bodies to be more sexy for example the sister had C cup breasts and afterwards they turned to D cup breasts one other thing the mark does to humans is tie the humans life the the mark giver

In the incubus harem is

The mom as the wife

The sister as a lover

The succubus mom a lover 

Your choice of anyone else 

The harem can have sex with any of its members