Descartes (デカルト, Dekaruto) is a large bandit who was after Vash the Stampede. He possesses a giant cybernetic arm with an attached boomerang which is his primary weapon. He is noted for being a notorious womanizer and his green mohawk. Initially in the series the varied rumors going around engineer a severe case of mistaken identity which leads to not only Meryl Stryfe and Milly Thompson believing him to be Vash the Stampede but attracts the attention of bounty hunter Ruth Loose, aka "The Constance Rifle". Amidst the multitude of rumors discussed there are mentions of a man with a red coat and blond hair, a short legged giant with a mohawk, and a man with a red coat and a huge weapon. Descartes notices Ruth's coat is lined with red, possesses a large rifle, and is blonde. The two battle as Meryl and Milly flee to warn the town below while the real Vash tags along. Meryl directs Vash to take her mount into the town with the incentive of $$10 to signal an evacuation and she rides with Milly back to the site of the battle. When they arrive they eventually discover that both Ruth Loose and Descartes have joined forces and Vash returns to rescue the girls. He haphazardly, yet soundly manages to defeat both Ruth Loose and the giant Descartes without ever drawing his weapon. Descartes' gang is apparently disbanded as all his minions flee after Vash disables him.
In Trigun Maximum, he is seen bound in handcuffs by the Feds. The feds offered to reduce his sentence if he complied to attack 2 people, Midvalley the Hornfreak and Gray the Ninelives. After throwing a few boomerangs, he was told to investigate and make sure that the targets were dead. It was during this investigation that Descartes seemingly dies by the hand of Gray the Ninelives. Literally. Gray pierces a hole through Descartes with one of the boomerangs which was lodged in Gray's chest.
- In the dub, his name was not mentioned, and was only featured in the credits.
- In the anime series, Gungrave, a minor character appears who shares their name with Descartes.