The Devil's Friend

You just lost your parents, the only people who loved you, in a house fire a month ago. You moved out a few years ago, so your house is intact, but you lost something far more precious than a house. You lost the only people in the world that cared about you, and now you have been diagnosed with a terminal illness, and so you won't die alone. You do the unthinkable; you decide to summon a demon. The story starts the moment you start the ritual to summon a friend in exchange for your soul. You are calling for someone, anyone to be your friend, and that's when she comes. You have no idea of her status as royalty, and she has no idea of your illness, nor do you tell her until months into the contract, and you are so sick you can no longer hide it.

At first, the demon is annoyed that they were summoned just to be your friend; they only wanted your soul and made the contract before finding out the only thing you wanted was not to die alone without someone caring for you. But later, as time goes on, the demon starts to warm up and care for the human. That then develops a true friendship together, and finally, in the human's last week alive, the demon realizes their feelings for the human, turning the human into a high-ranking demon and continuing to let their feelings grow.

Build a strong bond of friendship with the demon so you won't die alone, and later let it grow into something more. After the player's death, you will have to learn to adjust to hell as a high-ranking demon. You will have no idea of the demon being royalty till after your death, only finding out when you wake up in hell as a demon, and the demon will only find out of your illness after noticing your body weaken as days pass by and after you are too weak to hide how sickly you are.