This should be a Black Butler fanfic, borrowing a bit of background. Except for Charles Sebastian, these two children are just passers-by. It's considered a pseudo-fan. But they do appear occasionally, after all, they are cousins.
Protagonist: Betsy Dougal (Ciel's father's sister married into the Dougal family, so Bates was born.)
Demon: Lux
Appearance: Bates has blond hair, blue eyes, and a gentle temperament. After meeting the devil, he was in a wheelchair and was a cripple.
Lukes has white hair and red eyes. He is a bit irritable and talks well to the protagonist. After all, your Excellency dines once every three thousand years, so he always takes good care of food.
Text text:
A wish and a kiss. This was the devil's kiss, a kiss on his hands, a kiss on his eyes, a kiss on his lips, a kiss on his soul. This is a seductive and depraved kiss. When the kiss falls on his soul, the devil captures his soul and enjoys his soul.
Is that soul from three thousand years ago yours? My master.
Is this soul still delicious three thousand years later? My master.
I am the devil, using love as seasoning to cook the most delicious soul in the world.
I write when I'm bored, but I don't write when I'm not, haha.