His Monster by Viola Grace

Working at a game company is just a job, until a cosplay moment opens her eyes to another world beyond her own and exposes her boss for the demon he is.

Serene hasn’t wanted much out of life. A car, a house, a job, and a few friends. That was her list. She ended up with a house that taxed her to the limit, a car that died at work, and a job that paid too little for her to be able to afford a new vehicle. She was thinking about working elsewhere when an urgent request puts her in a situation she wasn’t too fond of.

Dressing up as one of the bosses in the game had become part of her job, but she hated doing it in public forums where guys got grabby. A day’s appearance at the convention dressed as the demon queen was an exercise in dodging pinching fingers. The moment she could relax for the display, the crowd went wild. She couldn’t turn to look, but the hand around her wasn’t human, and it pulled her back into what appeared to be the game that she had been seeing all around the office. She wasn’t a gamer.

A demon assigns her a few quests, she completes one without trouble. Seducing him is the other. When the demon reveals her boss’s face, she is a lot less hesitant.

Waiting for thousands of years for the woman reincarnated with the spirit of his wife has caused a lot of stress for the nameless god. Finding her was one thing, convincing the human soul that she was housed in to agree to let them reunite involved a detailed seduction. It was a good thing he had time to plan.