Rene has amiable character and is great at making conversation. He harbours a feeling of absolute hatred towards the Nazis. The skills he learned while he was in the Secret Service have made him expert in communications and techniques of infiltration and sabotage and has a natural instinct for imitation which probrably earned him his other nickname "Spooky". Beside speaking French he can speak English, German, Russian, and Italian fluently.
Being fluent in five languages allows him to infiltrate enemy lines wearing a stolen enemy uniform and divert or give deceptive orders to enemy soldiers. His attack involves silent and cautious movement and he attempts to use minimum force if possible. He has the ability to wear an enemy uniform for an infinite amount of time, or until a soldier of a high ranking sees through his guise. His preferred weapon is a syringe loaded with a lethal poison which eliminates his enemies in complete silence. He can lift bodies and hide them to avoid raising the alarm. The Spy is the team's medic when neither the Driver nor the Sniper are deployed on the mission.
- In the beta version of Commandos: Behind Enemy Lines, Spooky's appearance is much more younger than in the final version.
- He supposed to be featured in the second mission A Quiet Blowup as in the leaked image, but he was excluded in the final release of the game except in the mods.
- If the Driver is not present in each mission in Behind Enemy Lines, he can also drive any vehicle as long as he is in uniform. This feature is only in the mission Stop Wildfire which can use to block the enemy sapper from the detonator.
- In Commandos 2: Men of Courage, he only appears in European missions with the exception of Saving Private Smith. Unlike the other Commandos, he did not appeared in the Pacific missions (Target: Burma to The Giant in Haiphong).