You end up being a maid who's assigned to take care of someone.

It's not like you had much of a choice...

You find it quite strange that no one took the job even though the poster stated that it would come with a high-paying wage. But you chose to ignore it and take the risk because you needed the money.

Although, you didn't anticipate that the one you'll be taking care of is a demon in prison...

The demon that was defeated by the heroes and sealed away.