One must be careful when dealing with bad people.

Alternative form of better the devil you know than the devil you don't know

Seek to dispel ill-will before a day’s end, and not to act upon desires for vengeance.

Resembling a devil. / Characteristic of a devil. / (informal) Extreme, excessive.

(informal) Devilishly; very; exceedingly.

Devilry.

mischief. / Wickedness; cruelty. / An action performed with the help of a devil; witchcraft. / An act of such mischief, wickedness, cruelty, or witchcraft.

plural of deviltry

plural of devilry

The state or quality of being devilish.