Joachim de Wett was a Nilfgaardian noble who commanded the Verden Operations Group during the Second Nilfgaard War. His daughter, out of many other women, was rejected by emperor Emhyr var Emreis, so the emperor could marry the false Ciri. Because of that, he and other nobles formed a conspiracy to overthrow Emhyr and put Morvran Voorhis on the Nilfgaardian throne. Emhyr found out about this conspiracy from the traitor, Berengar Leuvaarden, however the sources are saying that Morvran Voorhis became the successor of Emhyr after all. Duke de Wett led his army in the decrepitude way, and his troops treated the Nordling civilians in very cruel way. He caused an uprising in Verden and king Ervyll of Verden, who was collaborating with Nilfgaard, was dethroned. He was slowing down the offensive in III phase of invasion and blocked, by that, the Middle Army, in the long term that was the main cause of the defeat of Nilfgaardian armies in the battle of Brenna. He was sentenced to death by Emhyr var Emreis.
- It is possible that Count Roderick de Wett (who appears only in The Witcher computer game) is related to Joachim as he is also from Nilfgaard.