Whether hostile to each other, indifferent, or strangers, different groups must fight on the same side. All the way up to an Enemy Mine situation. Afterwards, they are no longer hostile and perhaps even actual friends. If they continue as enemies, they are Friendly Enemy.
To my friend, the birthday boy of October 7th, Giacomo Offredi, you know what to do here. This is my myCast birthday gift to you.
REMEMBER: Don't do characters that haven't appeared UNTIL they have.
NOTE: This is like the Tropes of the Dawnverse, so this should be familiar
