Devil: "Don't be silly, why would we want the lich to win?"
Imp: "Because we're evil?"
Demon: "And that makes us all one big happy family? Screw that!"
The world is divided into two camps: good, and evil. Of course, all the good guys work together, but what do the evil guys do? Well, they also work together of course! Because if you are not good, you must be evil, and evil is one big happy family. Evil understands each other
, and they all have the same goal in mind: to destroy team good! So it is only natural for them to sing together in perfect harmony.
This trope could include instances where either evil or good beings mistakenly thing Evil Is One Big Happy Family