When the devil can't sleep

"What will I get in exchange for saving your brother ?" she says ruthlessly
"My blood"
"But honey, I already have it." A devilish grin shows up on her face.
"This is not the right time to make your damn ass deals! Save him, and I'll pay later!"
"Taking advantage of others' situations to make my deal that serves my advantage, therefore it's the perfect time to make such a productive deal. dear 'Lucifer' I'm aware of what you want... but I want a price for my efforts, something precious in return."
"Like what? I'll give anything I have to save him! Just name it!"
"Anything? Are you sure of what you're saying, sugar cube?"

people look for eternity, but her...nuh she just wanted to be dead.
she had slept so long, but she opened her eyes again,' Zira' found herself in a different world, but she still had the same person with the same body and memories.
every time Zira closed her eyes, seeking some rest, her world changed all alone, incapable of dying, more powerful. After a hundred years in a new world, she met for the first time the devils "Lucifer" and "Satan" two devils related as brothers each one of them wanted something from her, and she wanted only one thing 'rest' that won't require her surrounding people. Until a fourth person gets engaged in their life trying to help her find her eternal riddance.

what kind of relationships will they have when she still has her insomnia?