They can't use Pistol secondary weapons.
Mercenary is a highly offensive class. They can deal lot of damage with explosives and machine guns. They start with a default SMAWG. Mercenaries work best alone, because they use Explosive weapons, just like Engineers, which can harm their teammates, or themselves. Because of that you shouldn't fire grenades from grenade launchers massively near your squadmates. Mercenaries are the second most tankiest characters in the game, Juggernaut being the most tankiest.
Mercenaries can use two killstreaks: Betsy and Ghost Weapon. Betsy is a powerful cannon with high ammo capacity and long range. Ghost Weapon gives another invisible weapon to the mercenary, so every shot fires two projectiles. This is highly recommended for use with machine guns, but doesn't work with rocket launchers (excluding the M202 which has more than 2 rockets).
Mercenaries are usually shirtless and always have large, muscly bodies. They are the biggest soldiers on battlefield, second only to Juggernaut. They can have a beret, or hairs like Engineer and Sniper. Dex is the only hero in the game who has a beard.
Explosive Temper: increases rate of fire by 25% when health is below 40%
Status Proof: Status effects expire 2x quicker
Dex is a former member of Strike Force Heroes 2 team and unique mercenary.