Yves Grosclaude was a Havenite citizen and diplomat.
He was originally a Dolist, and served as the Republic of Haven's ambassador to the Star Kingdom of Manticore under the Pritchart administration. He and Arnold Giancola were old friends and conspired to alter diplomatic notes between the Republic and the Star Kingdom. This eventually led to the Second Havenite-Manticoran War. (HH10)
Later Arnold Giancola ordered Jean-Claude Nesbitt to assassinate Grosclaude, who died in a suspicious Aircar accident that was publicly called a suicide. (HH11)
By 1921 PD, based on information that Victor Cachat and Anton Zilwicki obtained on the planet Mesa, it was assumed that his death was caused by the Mesan "Rat Poison" nanotechnology. (HH12)