devil lies in the details

dance with the devil

To engage in risky and immoral behavior.

devil dancing

Risky, reckless or potentially immoral behavior.

devil in disguise

A person or thing that appears to be good, honest, or upstanding, but is inherently nasty, evil, or damaging.

folk devil

A person or type of person blamed by the public for various ills, as during a moral panic.

give the devil his due

To acknowledge the positive qualities of a person who is unpleasant or disliked.

pack of lies

Total lies, complete untruth

play the devil with

To cause great trouble or distress to.

spare someone the details

to not give details about something mentioned, usually to avoid embarrassment or irrelevance