Pyro

The Pyro is a class who wields a Flamethrower as its main weapon. Along with the ability to inflict burn damage and a relatively high damage output, the Pyro also has the airblast mechanic, which can neutralize an enemy's uber with ease, reflect projectiles like rockets and arrows, and extinguish burning team mates.

6v6

Main Article: Pyro (6v6)

In 6v6, the Pyro is considered an offclass. Most commonly run when the defending team has über disadvantage while defending last, the Pyro's job is to neutralize the enemy team's über through the use of the airblast mechanic along with compression blasting away spam from the Soldier and Demo.

Highlander

Main Article: Pyro (Highlander)

In Highlander, the Pyro is considered a support class. The Pyro's main job in Highlander is to protect the Medic. It also has the jobs of displacing and neutralizing enemy ubers, spychecking to neutralize the enemy Spy, protecting its team's sentry gun by deflecting projectiles, and providing flank support when required. The pyro most commonly positions himself around the combo, so as to allow them to deal a lot of damage to the enemy team's damage dealing classes like heavy or demoman, without having to focus on classes like spies or scouts. This allows for the rest off your team to co-ordinate a push. Alternatively, if his team is aware enough off the enemy spy, then the pyro could take the role of a roaming pyro. This involves the pyro flanking the enemy team, and trying to deal a lot of damage, possibly to get a pick on the medic, which could then allow your team to push in.