As a young man he was a knight errant and formed a knightly team with close friends, Vladimir Crespi, Ramon du Lac, and Milton de Peyrac-Peyran. Sometime later they received a mission from the ducal couple to escort Sylvia Anna, older sister of Anna Henrietta and who was said to be under the influence of the Curse of the Black Sun, beyond the boundaries of the duchy. He and his friends fulfilled the task and took the teen to Caed Dhu but not before they abused her in each their own way, with Louis insulting and mocking her. They then left her at the edges of Caed Dhu, in a ragged dress, penniless, and in the cold, hoping that she would soon die. However, he eventually diverged paths and stopped being friends with some of the group.
He believed that the new times and customs required that knights change their attitude towards life and entrepreneurship, which he believed should become a sixth chivalric virtue and took up the grain trading business using a mill that he inherited from his mother and which made him a sizable fortune. Palmerin de Launfal maliciously even nicknamed him "Sir de la Stingy".
He later met Dettlaff van der Eretein as a customer of the young Bootblack in Beauclair, where they quickly became friends after de la Croix chased off a customer who'd cut in front of Detlaff, and one day in 1275 the two went to see the old mill. During the inspection of the building Dettlaff killed the count by piercing his heart, stuffed a bag of florens down his throat as a symbolism of not embracing the chivalric virtue of generosity, then quartered his body and threw the pieces into the river. Overcome by guilt for murdering a friend, Dettlaff then cut off the hand that pierced the count's heart and threw it into the river.
The remains of the count were noticed by the fisherman Linus and by the Innkeep of The Cockatrice Inn, who called the Ducal Guard. The body parts were then fished out of the river and took to Corvo Bianco, which had been temporarily converted into a morgue. Geralt investigated the shallows and networks with Milton, where the body was found, and noticed a monogrammed handkerchief by which the corpse was identified.