do u mean attacker and defender? well, if yes, therefore, zombies are attackers and humans are defenders.
Question answered. Defenders = Humans Attackers = Infected Locky Lock? Also, the 3rd team, 4th team are for Muli Team games. I think Red = Defenders, Blue = Attackers, Green = 3rd team, etc.
by the way, in case you come back with this question, when in forge, you have to switch the gamemode to "Infection" for you to be able to use them