Spanish Civil War
In April 1937, she was part of Ignacio's cell who were on their way to Barcelona. Consisting of Miguel Carasso, American Dwight Adams and several other Republican soldiers, the group set up camp in the wilderness to rest for the night. As they shared stories around a campfire, the group was attacked by Republican soldiers, who had mistaken them for Nationalist soldiers.
By May 1937, the cell had made their way to Barcelona. One night, Glaucia discussed with Ignacio over cigarettes of the reason she was unable to sleep, as she was haunted by memories of the 26 April bombing of Guernica. The two were interrupted by a noise, which she investigated and found a man with a trenchcoat eavesdropping on their conversation. Glaucia chased the man through the rooftops, eventually catching up to him through the rooftop.
The man revealed himself as Norbert Clarke, an Assassin sent by the British Brotherhood as their backup. Refusing to believe the Assassin, Glaucia threatened him with a knife to which he responded saying that he was the one responsible for taking down the entire Templar branch in Talinn, Estonia in 1936. Convinced that he is not a Templar, Glaucia and the rest of the Assassins introduced themselves to him.
The next morning, Glaucia and the Assassins trained with Norbert to test his skills first hand, in which they were easily defeated by Norbert. The cell later followed Ignacio and observed a firefight between the anarchists and the communists. She later watched as Ignacio held the Koh-i-Noor which unleashed several serpent-like projections that almost consumed the Assassins. As Ignacio passed out from the incident, Glaucia and the group checked on him, not unaware that the Black Cross Albert Bolden was observing them from afar.
Joining the Instruments
When the Albert went after Norbert, Glaucia and the Assassins attempted to stop him. When the Black Cross takes the unconscious Ignacio instead, she was unable to stop him from doing so. Glaucia would later stand alongside Norbert and the Assassins during the stand-off against Ignacio and Albert Bolden, unaware that Norbert Clarke was dead and that their guest was in fact the Templar Rufus Grosvenor.
During the fight against the Assassins, Albert fought against Dwight and Miguel, who were told that Ignacio was converted to the Templar side by Bolden, while Glaucia took Cardona hostage, putting a knife on his throat. Ignacio tried to tell Glaucia about Grosvenor, but she revealed to him that he already told her who he was and that she didn't care, only wanting to become an instrument of the "Gods" from now on. After he killed Adams and injured Carasso, Albert threw his bladed pin toward Glaucia's face, but Ignacio caught it with his bare hand as a delusional Glaucia stated that the gods wouldn't allow her to die. Ignacio then kicked his lover in the chin with his elbow, knocking her out, and the two men followed Miguel who had fled to Clarke.
Following his tracks to the town church, Bolden and Cardona were greeted by Grosvenor, who was standing over a pit of anarchist bodies, killed by Franco's men, and who ranted about humanity needing the firm guiding hand of the gods. Entering the church too, Glaucia and Miguel took aim at them and had Ignacio and Albert to surrender their guns. Grosvenor told of how his master had followed Ignacio's bloodline, hoping for optimum conditions - but the fact that he was a male was a clear failing to fully controlling the gem.
Nevertheless, he offered Ignacio the Koh-i-Noor in the hope that he may still try. Upon touching the gem, the Assassin created the illusion of the diamond shattering under its own power and summoned creatures of energy who stampeded into the walls of the church bringing it crashing down upon all of them.
Some time later, Albert dug through the rubble, and managed to extract Ignacio from the ruins. After he told him that the destruction of the diamond was just an illusion and inquired about the fate of his former lover, the Black Cross revealed to Ignacio that he saw both Grosvenor and Glaucia leaving the destroyed church, stating that they probably left for United States.