Pyro - Not only do you enjoy setting enemies ablaze, you are also clinically insane. You show your enemies no mercy as you send out steady streams of fire with your flamethrower, and let out muffled laughs from underneath your gas mask.
Engineer - Don't need nothin' but your wrench. You are your team's ultimate defense, and waste no time setting up a sentry gun to protect your team's briefcase. You are also responsible for setting up teleporters for quick transportation, or dispensers to supply your teammates with health and ammo