The Spy, hailing from an indeterminate region of France, is a fan of sharp suits and even sharper knives, and relies on stealth and trickery to aid his team. Using a unique array of cloaking watches, he can render himself invisible or even fake his own death, leaving unaware opponents off-guard. His Disguise Kit lets him take on the form of any class on either side, allowing him to blend in while behind enemy lines before literally stabbing his unsuspecting "teammates" in the back. In fact, a swift backstab with any of the Spy's knives will kill any foe in a single hit - providing they aren't under the effects of any type of invulnerability or damage reduction.
In addition to being able to assassinate key enemies quickly and efficiently, the Spy has advantages over the Engineer. Using his Sappers, he can disable the Engineer's buildings – slowly draining their health until they are destroyed unless removed by an Engineer or a Pyro wielding the Homewrecker or Maul. He can also make use of enemy Teleporters to surprise (and maybe even telefrag) his foes.
Three other common Spy targets are the Heavy, Medic and Sniper. While the Heavy is the slowest class to begin with, he is even slower when he has one of his Miniguns spun up – this slower moving speed, along with the distraction of combat, makes for an easy opportunity for a backstab. Medics must focus on their healing target, which also leaves them vulnerable to backstabs. Snipers are obvious Spy targets due to their slower movement speed and lack of nearby awareness when scoped in with their Sniper Rifles. Snipers can use the Razorback to defend themselves from a single backstab, which also stuns the offending Spy.
Whereas most players can only see the names and health of their teammates, the Spy can observe the names and health of the enemy team as well, allowing him to relay useful intelligence. Only the Medic carrying the Solemn Vow shares this ability.
The Spy is voiced by Dennis Bateman.