factional - A group of people who all team up, like in a game, and they

A group of people who all team up, like in a game, and they fight with other groups, like a bunch of angry cats.

My faction in the game fought with the other faction like they were enemies.

The faction at the party was the best, and they cussed everyone else out.

In the RPG, the faction was so strong, they could beat up the whole kingdom.