- "An eye for an eye, John. You know how it goes."
Cassian is a hitman, bodyguard and the right-hand man of crime lord Gianna D'Antonio, leader of the Camorra crime syndicate and an old colleague of John Wick. As with many other assassins working in the criminal underworld, he is a one-time acquaintance of John.
Cassian serves as a major antagonist in John Wick: Chapter 2, during which he hunts down Wick because he killed Gianna D'Antonio, whom he was close with, throughout the movie's second and third acts.
Cassian accompanies Gianna D'Antonio to a secret concert in the catacombs of Rome. After guarding Gianna for some time, Cassian is sent away to entertain the guests while she changes her make-up. With Cassian absent, John Wick is able to approach Gianna alone. After a brief conversation, Gianna commits suicide by slitting her wrists in her bathtub.
John encounters Cassian on his way out, and Cassian immediately realizes why John has come. After a brief calm, both draw their guns and shoot; however, due to both men wearing protective armor, they remain unharmed. While John escapes into the crowd of concertgoers, Cassian sends the security after him. The bodyguard rushes into Gianna's chambers, where he discovers her corpse in the bathtub.
Revenge on Wick
John fends off Santino D'Antonio's men (sent to kill John as a measure to tie up loose ends) and escapes the catacombs, whereupon Cassian rams him with a car. The bodyguard jumps out of the car and another gunfight ensues. After their guns run empty, the two engage in a brutal fistfight that carries throughout the streets of Rome, and they end up crashing through a window of the local Continental hotel. The battle swiftly ends with a stern reminder from the manager, Julius, that no business may be conducted on Continental grounds. He advises the two to go to the bar to calm down.
John and Cassian discuss their motivations over a drink. John explains to Cassian that he killed Gianna because Santino forced him with a Marker. Cassian understands John's actions, but also expresses that he has a duty to avenge his ward.
Santino puts a bounty of seven million dollars on John's head. Every assassin in New York comes after John; in addition, Cassian flies in from Rome to exact revenge on John. The two engage in another fight in a public area, equipped with silenced guns. John flees to a subway station, where he encounters other assassins. He stumbles upon Cassian again, who is watching him from the other side of a train platform. Both men board an incoming train. The two get closer and closer to each other as the crowd of passengers dwindles, and when the train is almost empty, they draw their knives and attack. John gets the upper hand and drives his knife into Cassian's chest. John sits Cassian down, and explains to Cassian that the knife has punctured his aorta and that he has a choice to make; either pull it out and bleed to death or leave it in and stop the hunt, which will give him a chance to live. John disembarks the train at the next station, leaving behind a grimly smiling Cassian.
Cassian does not return to John Wick: Chapter 3 – Parabellum, thus it can be reasonably assumed that he either:
- Bled out and died from his stab wound
- Survived his injury and decided not to further pursue John.
Alternately, he may have survived but decided to rest and recuperate in order to attack John again some time in the future, as his chest wound was quite severe and would require several weeks to recover. It is possible he will appear again at some point in the John Wick universe; however, his current status remains unknown.
Cassian is a very serious, stone-faced man, much like John Wick. He seeks revenge on Wick for killing Gianna D'Antonio, much like Wick seeks revenge for the death of his dog in the first film.
- Expert Combatant: Cassian is an excellent fighter, and can almost match John Wick in combat, but this mainly due to John Wick being exhausted after the fight in the catacombs of Rome and also being hit by a car drove by him. But it is safe to say that he is an extremely martial artist skill.
- Knife Proficiency: Cassian is skilled in the use of knives in melee combat, being able to briefly hold his own against John Wick in a knife fight
- Skilled Marksman: During several of his confrontations with John Wick, Cassian shows great skill in the use of firearms
Armored suit, gun, knife, silencer.
Cassian has a pistol, machine gun, silencer, knives, and likely many other weapons.
- Arsenal Firearms AF-1 Strike One: Cassian used this pistol against John in Rome and attached a suppressor to it during his assassination attempt on him in the subway.
- M1911 variant: Cassian also attempted to use this pistol against John in Rome, but he was disarmed.
- Cassian was the second character to fight John Wick onscreen and survive, after Kirill.
- He has a tattoo of a scorpion on his right hand.