In John Wick: Chapter 4, Keanu Reeves And Donnie Yen Are The Year's Greatest Frenemies

This post contains spoilers for "John Wick: Chapter 4."

In the world of John Wick, you simply never know which anonymous face in the crowd is hellbent on trying to kill you or what unexpected ally might suddenly arrive to help you out of a jam. The line between hunted and hunter has never been thinner than it is in "John Wick: Chapter 4." As the reluctant assassin's revenge tour reaches its crescendo, it becomes painfully clear to both Keanu Reeves' Wick and the audience that actions have consequences that ripple out far beyond our hero's grief-stricken shortsightedness. The greatest trick that the fourth film pulls comes from externalizing this idea through the introduction of a new character: Donnie Yen's Caine.

Caine isn't too far afield from the typical secondary villain established throughout the "John Wick" franchise. The first "Wick" sequel had the likes of Adrianne Palicki's Ms. Perkins and Cassian (Common), while Mark Dacascos' Zero in "John Wick: Chapter 3" gave us another of Wick's former assassin associates who have become all-out enemies. Their murky motivations may differ and their methods are entirely unique, but they all waver on the knife's edge between admirer and antagonist. But, until this point in the franchise at least, none ever received the level of depth afforded to Caine. Pulled out of retirement for one last job, Caine must hunt down and kill his old friend John ... or pay the ultimate price through the death of his innocent daughter.

Even though we never actually see Wick and Caine together in their glory days, the reluctant tension between them adds a whole new dynamic to every one of their interactions and fights in "Chapter 4." In short, they're the best frenemies we'll likely ever see on the big screen this year.

Respect and reputation are everything in the assassin underworld of the "John Wick" movies. Built on a foundation of clearly-defined rules, the whole enterprise depends on a code of conduct befitting these high-class killers. That means that all other priorities — loyalty, friendship, and even love — come second to duty. Caine fully embodies this awful ideal right from his introductory scene, when the villainous Marquis de Gramont (Bill Skarsgård) summons him and tasks him with killing the troublesome Wick, once and for all. It's quickly established that the blind assassin (as the Marquis so succinctly puts it later on) has something to kill for, something to die for, and something to live for. He and John have obvious mutual admiration for one another, but what does that matter when family is at risk?

John Wick knows this burden all too well, having previously retired from this life himself to settle down with his wife Helen (Bridget Moynahan) ... only to lose her anyway. One can easily imagine the two bonding over their respective attachments, struggling to balance their violent lives with their domestic ones before finally getting out of the game altogether — or trying to, at least. In both their cases, the past comes back to bite them and drag them unwillingly back to the job they left behind.

When they come to blows repeatedly throughout "Chapter 4," it's unlike any other action sequence in the film. The hard-hitting and downright balletic fight choreography between Yen and Reeves comes laced with a sense of melancholy, almost as if neither can quite bring themselves to deliver the killing blow. Genuine friends are in short supply in the assassin business, so of course fate put two of them on a collision course.

The bulk of the plot in "John Wick: Chapter 4" is concerned with getting Wick to survive long enough to reach the appointed duel at dawn with Caine, serving as a proxy fighter to the cowardly Marquis in the ultimate fight for freedom. The stakes ensure that audiences remain fully dialed in amid all the carnage leading up to it, with everything before that face-off serving as extended appetizers (okay, maybe a lot of dessert, too) until the main course. The film, however, wouldn't feel complete without throwing audiences one more bone: the team-up between Caine and Wick as they fight their way up the Sisyphean-like staircase.

With only minutes to spare before the duel begins, John has to fight his way past hordes of assassins — but he can't do so alone. Thrown back to the very bottom of the stairs after all that effort in the most hilarious and deflating moment in the movie, Caine finally arrives to help his friend make their crucial appointment. What unfolds next is one of the best sequences director Chad Stahelski has committed to film, translating the unlikely twosome's complicated history into graceful, gory action before immediately putting them at odds again during the duel. Fittingly, the pair have one last twist up their sleeves that allow both to escape, bloodied but victorious.

Enemies to allies is a time-honored trope for a very good reason, from the Terminator and Sarah Connor all the way to Kylo Ren and Rey in "Star Wars: The Last Jedi." It was only a matter of time before "John Wick" tried its hand at it and, in the end, we received one of the highlights of the entire series. With Wick and Caine, "John Wick" saved its best action duo for last.