Equipped with the Corvix Blades, the Crows were able to emulate the killing techniques of the Assassins, striking their prey from the shadows or under cover. From 1503 to 1506, they exploited these skills not only in their assassination of Cesare's enemies, but also on hapless peasants throughout Tuscany. Despite their status as a covert force, they frequently launched brutal raids against villages and farms, massacring civilians for sheer sport. Such stories reached the ears of Niccolò Machiavelli of the Assassins, but he was slow to react. It would not be until the Crows threatened the life of Leonardo da Vinci one day near the Basilica di Santa Croce that they finally piqued the Assassins' notice.
A couple of years later in 1506, Lo Sparviero, the same Assassin that had saved Leonardo's life recovered a pair of Corvix Blades—alongside the stolen Hidden Blade blueprints—in Rome. A while later, he rescued a man who plotted to murder Cesare but failed and was scheduled for execution. This man, Demetrio il Silente, was in fact the scientist forced by Cesare to create the Corvix Blades, and he confirmed that the weapon retrieved by Lo Sparviero was a prototype of the blades. He shared with the Assassins all that he knew of the Crows, including the history, origins, and Cesare's reasons for its foundation.
Sometime afterwards, the Crows took over the Colosseum, where they were receiving a large shipment of Corvix Blades and Crow uniforms. The Assassins took heed and sent Lo Sparviero to investigate. Matteo Favero, Sirus' son and a Crow Leader, was killed at the top of the Colosseum by the Assassin, and the Crows were forced to evacuate when more Assassins invaded the camp. There, the Assassins captured Sirus, who claimed to be only a weapons merchant forced to work with the Crows and that he despised Cesare.
The latter was not technically false: in the years prior, tensions had escalated between Sirus and Cesare owing to disagreements over ideology and direction of the group. By the time of his capture, Sirus had come to loathe Cesare, who declared that his organization had gone rogue in turn. Sirus entered into Machiavelli's confidence, proving his loyalty by helping the Assassins sabotage the Borgia's plans on numerous occasions, a matter that did not conflict with his goals. All the while, he plotted the day he would take revenge against the Assassins for the death of his son.
Weeks into his infiltration, Lo Sparviero recovered a ledger from one of Cesare's personal bookkeepers. Using a special decryption device provided by Sirus, Machiavelli was able to decipher the ledger, learning for the first time that the Crows were led by a man called Il Corvo. Months later, with the Assassins no closer to discovering the identity of this leader, Sirus advised that they might find a lead by intercepting the letters delivered by Borgia messengers to the Crows.
Meeting with Lo Sparviero at the Castel Sant'Angelo, Sirus identified one of these Borgia messengers, who Lo Sparviero swiftly killed for his package. He handed it to Sirus as requested, but when the merchant instructed him to then lay low while he located the Crow hideout, the Assassin found this exceedingly suspicious and began following him. Whether this had been Sirus's plan or not, he was well aware that Lo Sparviero was tailing him and lured him into an ambush by his Crow Leaders. The Assassin slew all the Crows and chased after Sirus, who proclaimed his thirst for vengeance before escaping using his tricks. Eventually, Lo Sparviero was forced to return home as he lost track of the Crow Master.
Now exposed as Il Corvo, Sirus began his grand preparations for a major assault against the Assassins. He sent letters to all his members spread out across the region summoning them to Rome, where they were to rally for their climactic operation. Once most of his forces had arrived, he fortified himself at the Castel Sant'Angelo, sending his agents out to attack the Assassins and their allies throughout the city before his enemies had a chance to group.
The Crows' sudden onslaught seemed to assure a decisive victory. The Assassins had received advanced intelligence of their plan, but had not been quick enough to act against it; Machiavelli himself had arrived in Rome only on the day of the attacks. Though he had only been able to summon one Assassin, Lo Sparviero, this proved enough. While Sirus commanded his forces from the entrance to the castle, believing that his reinforced bridge would be adequate defense, Lo Sparviero sneaked to him by traversing underneath it.
The Assassin surprised him and his bodyguards and killed all of them. Despite outnumbering the Assassins with an army, the Crows' morale broke and many surrendered. The Borgia forces began to assert authority, destroying the Crow hideout shortly after the Assassins raided it. With this defeat, the Crows dissolved as an organization, with the few survivors fleeing to Forlì where they would be eliminated shortly afterwards.
Originally a special branch of the Templar Order, the hierarchy of the Crows was simple, composing only of two ranks: Initiates and Crow Leaders. While Initiates wore plain black clothes over their armor, only the Crow Leaders were permitted to wear their iconic crow-feathered uniforms and wield the Corvix Blades.
The Crow forces also consisted of more conventional soldiers, all whom donned the group's black color scheme. These soldiers were modeled after the Borgia army and comprised specialized units such as crossbowmen, Agiles, and Brutes. By the time of their final operation, they also incorporated a sizable number of Papal Guards in their ranks.
Conceived as a counter-Assassin unit of the Templars, the Crows were trained firsthand in the martial arts unique to their adversaries. They were meant to be a shadow organization who, like their enemies, achieved their aims through assassination. For that reason, they mirrored the Assassins' agility and expertise at stealth and evasion.
So successful was their replication that they outsmarted even the Assassins on various occasions, eluding their detection for the first several years while they pillaged farms on the countryside. Their aptitude for disguise was uncanny; Assassin agents could not even identify any of the Crows without the aid of Eagle Vision even when they were wearing their trademark crow-feathered clothes. Having received direct instruction on the tactics of the Assassins, their agents often knew when to expect an Assassin on their tail or how to detect one. It was a common strategy of theirs to feign ignorance before luring the Assassin into a trap.
In their assaults on commoners throughout Tuscany, their favored tactic was to materialize out of the darkness and launch a swift but brutal assault before their victims had a chance to compose their defenses. They would employ a similar strategy of shock and awe in their last attempt to overwhelm the Assassins.
Iconic to the Crows were the Corvix Blades, modified Hidden Blades identified by the head of a crow carved deep into their blades. Aside from this weapon, they wielded exotic swords and were distinguished by their uniforms: jet-black leather armor, decorated with crow feathers and complete with a small cloak. Only the Crow Leaders were entitled to the signature uniform and Corvix Blades, and most of the regulars in their army utilized the conventional weapons and armor of their day.
- In Assassin's Creed: Identity, Crows encountered in the cities in disguise wear black or dark grey versions of normal civilian clothes. Upon being identified by Eagle Vision or when they spring their attack, their outfits morph into their full, feathered battle armor.