- "I've always thought of myself as a gang leader. Firm, but fair. We'll have uniforms, and I'll unite a mix of disenfranchised outsiders under one name. […] We'll call ourselves the Rooks."
- ―Jacob Frye, February 1868.[src]
The Rooks were a crime syndicate active in London during the 19th century and early 20th century. At the height of the Industrial Revolution, the Rooks were led by the Assassin siblings Jacob and Evie Frye.
Founded in March 1868, the Rooks were formed through the liberation of the last remaining criminal competition to the Templar-controlled gang Blighters, the Clinkers. Led by the Fryes, the Clinkers and other volunteers formed the Rooks. The criminal syndicate was regularly involved in fighting the Blighters and vying for influence and territory in the city. This was done mainly through overrunning the Blighters' strongholds, hunting their members, liberating the child laborers in Blighter-run factories, and eventually engaging in gang wars. By eliminating the Blighters' leaders of each borough, the Rooks thrived as they gained recruits from their rivals, and eventually had control over all boroughs.
In 1888, a former Assassin initiate, who would soon become known as the infamous Jack the Ripper, usurped control of the Rooks from Jacob, and elected to use Whitechapel as the center of his operations. Jack trained the Rooks in combat techniques that would allow them to better challenge the surviving Assassins in the city. Under his orders, the Rooks provided security for Lady Olwyn Owers' brothels, reopened fight clubs, trafficked opium and stole antiquities from the colonies. The Rooks also yielded multiple lieutenants for Jack, working willingly for their 'Mr. Jack'. 
- A rook is a member of the crow family of birds, asserting the continued connotation of Assassins and avians.
- The Rooks' symbol depicts a rook clutching onto a chess piece, the knight, marked with a Templar cross, symbolizing the Assassins', and by extension, the Rooks' goal of getting rid of the Templar Order and their gangs. This is likely intended as a visual display of "Rook takes Knight" as a rook is also a chess piece.
- Under the Fryes, Rooks wore green. Under Jack the Ripper, Rooks wore black.