Hunting the Koh-I-Noor
Before World War I, Grosvenor was a member of the Templar faction which followed the Master Spy. Twelve years after the death of the Sage, Grosvenor found the trace of the missing Albert Bolden in a Chinese opium den. He tried to blackmail the former Black Cross, threatening to reveal to the Order that Bolden was alive if he didn't gave him the Koh-i-Noor, but Bolden refused and disappeared while Grosvenor was turning his back on him.
As a result, Bolden resolved to take the Piece of Eden from the Swiss bank it was secreted in and constantly moved around the world with the diamond on him. During nine years, Bolden escaped the Templar goons that Grosvenor sent after him until he fell into a trap. Having discovered the location of Bolden's family and that his prey was regularly visiting the place to check on his loved ones from afar, Grovenor raided the house and butchered the Boldens as well as their dog to make a macabre scene and to lure the Black Cross inside. As a distraught Bolden discovered the gruesome fate of his family, a hidden Grosvenor used his distraction to knock him out and to take the artifact before fleeing.
Needing someone with a high count of Isu DNA to unlock the powers of the diamond, Grosvenor went to Spain where he planned to manipulate the Assassin Ignacio Cardona to do so. To approach Cardona, the Templar stole the identity of Norbert Clarke, after he manipulated the veteran British Assassin sent to help his Spanish brethens into taking his own life.
When he arrived at the Barcelona hideout, Grosvenor sneaked inside but Glaucia Acosta wounded him. He ran to the rooftops with Acosta in pursuit. She eventually caught up with the two of them coming crashing down through a broken roof. Playing the act, the Templar presented himself as Nobert Clarke, their Assassin backup sent from London.
They safely returned to their hideout, where the Spanish Assassins interrogated Rufus as to why he was the only backup that was sent considering how desperate they are for help. "Norbert" revealed that he was the Assassin who famously eliminated an entire Templar branch in Tallinn the year before, which instantly won him the approval of the Spaniards. Cardona requested that the team train with their British brother on the rooftop to see his skills first hand while he ventured out to try and find new weaponry, as their current ones were in a bad state of repair. During their training, Rufus and the Spanish Assassins started discussing the split between the anarchists and communists within the community.
Soon after, Ignacio ran past the group, insisting they all follow. They reached a fevered gun battle between anarchists and communists, with the team undecided on which faction to side with. Using this opportunity, Grosvernor offered Cardona an alternative, saying that the latter could make the team stop their in-fighting. The Templar then pulled the Koh-i-Noor out of his pocket and offered it to Cardona, who stated that he felt it calling to him and touched the diamond.
Immediately his eyes started glowing with a blue energy, and serpent-like creatures of energy emerged from the Koh-i-Noor, encircling and wrapping themselves around everyone. With blood pouring from his eyes and nose, Ignacio dropped the diamond and passed out. From a nearby rooftop, the former Black Cross Albert Bolden, who wanted revenge on Grosvenor for the murder of his family, observed everything that transpired.
Being pursued by the Black Cross
Bolden attacks Grosvenor without much success due to the Assassins surrounding him. He later takes the unconscious Cardona away and escaped, leaving Grosvenor with the Assassins. After the encounter, Grosvernor, still under the guise of Clarke, manipulate the other Assassins to stand on his side and recruited Acosta into his cult. Knowing that Bolden and Cardona would pursue him, he and the Assassin cell waits for them at a war-torn village.
His speculations were proven to be true, as Bolden and Cardona later arrived at the village. The both of them later confronted Grosvernor, who had hold up in the village church, standing behind a mass grave. In a last ditched attempt, Grosvernor and the Assassins managed to convince Cardona to use the Koh-i-Noor, who attempted to unleash it. However, his plans backfired as Cardona, who managed to resist the gem's control, directed it towards Grosvernor, which unleashed a series of animal-like apparitions and energy which ravaged the village and caused the church they were in to collapse. Grosvernor, however, survived the destruction and fled with Acosta to the United States, having believed the gem to be destroyed.
Equipment and skill
Rufus was a skilled warrior, able to impersonate an Assassin considered one of the British Brotherhood very best fighters and renowned for single handedly eliminating an entire Templar branch by himself. Rufus was a capable freerunner and climber managing to scale the buildings of Spain quite easily. He was also highly skilled in unarmed combat, managing to easily best three Assassins while sparring. Rufus was also a highly skilled tracker managing to locate a disguised Albert Bolden in China as well as find the location of Bolden's family without any knowledge of the man's history.