Following the introductions, du Casse, Rogers and Kenway passed the time with a shooting session, as Torres was not yet ready to meet with them. After Kenway beat Rogers' shooting challenge, du Casse noted the absence of "Duncan's" Wristblades, which Kenway explained to be due to his previous pair having been damaged beyond repair. Du Casse then handed Kenway a new pair that he had collected from dead Assassins.
Before their meeting with Torres, du Casse and Rogers requested that "Duncan" show his skills in assassination techniques; thanks to Kenway's freerunning abilities, he was able to mimic these techniques with very little effort. The three then went to join Torres, who, after inspecting the blood vial Kenway had brought with him, led them inside, where he officially inducted them into the Order.
Torres subsequently revealed his plans of locating the Observatory, with the help of a Sage named John Roberts, which would further the Templars' goals of a New World Order. Du Casse expressed his skepticism to the credibility of a Sage, noting it had been over four decades since the last Sage was found, though Torres reassured him they were certain. After toasting their schemes, the group of Templars made arrangements to convene the next day at the Castillo de San Salvador de la Punta and then retired for the night.
The next morning, du Casse and his Templar allies met the captured Roberts, and mentioned that a Sage's blood was required to enter the Observatory. While escorting Roberts to Torres' mansion, the Templars managed to fend off an Assassin attack, during which the Sage was nearly able to escape. With Rogers leaving for England, the other Templars decided to imprison Roberts and interrogate him the day after.
However, Roberts managed to escape later that night, leaving a trail of bodies in his wake. When the Templars arrived at the prison, they found Kenway instead, who had just arrived with the intention of interrogating Roberts himself. Realizing he was an imposter, the Templars apprehended Kenway and sent him to be taken with the Spanish Treasure Fleet as a prisoner.
- ―迪卡斯的遗言， 1715年。[来源]
Following this turn of events, du Casse earned Torres' trust and was tasked with ensuring a constant flow of weapons, ammunition and gold to the Grand Master. As well as this, he was appointed captain of one of Torres' largest galleons, El Arca del Maestro, which du Casse would frequently dock in the natural cove of Great Inagua, his island hideout.
Unbeknownst to du Casse, however, Kenway had escaped his imprisonment aboard the Spanish Treasure Fleet, and later sought to acquire El Arca del Maestro, so that it could be used as a defensive measure for the pirate republic of Nassau. To achieve this, and prevent news of his survival from getting back to the Templars, Kenway infiltrated the island and bypassed du Casse's guards. While du Casse was busy preparing for another voyage, Kenway snuck onto the vessel's rigging and struck the Templar from above.
As he lay dying, du Casse berated Kenway for his small ambition and ignorance, calling him a "parasite", though the pirate ignored these words and took the key that was in du Casse's possession. Refusing to tell Kenway about the key's function, du Casse cursed the pirate, before passing away.
Kenway would later take du Casse's hideout for his own, renovating the village and manor, and collect the four other Templar keys to gain access to a special set of armor.
- Julien是Julian的法语变体，最终可追溯到希腊语ιουλος (ioulos), 意思是“柔和的胡须”。