How does a taciturn solo killer have so many pals? The films’ creators can’t really explain, but each character has a raison d’être in this world.Over a run of three stunt-laden films, John Wick has dispatched his enemies with rifles, pistols, swords and knives, as well as an assortment of things that just happen to be nearby. On one occasion, he took out several foes by slamming into them with his ’69 Ford Mustang; on another, he beat a man to death with a library book. And then there was that time Wick slaughtered three men in a bar with a pencil, a feat that his fellow killers can’t seem to stop talking about. Wherever Wick goes, folks die.So why does John Wick, that most lethal of assassins, have so many friends?In a clear break from the tradition of cinematic lone-wolf assassins with few if any pals — Clint Eastwood as the Man With No Name; Chow Yun-fat in a series of John Woo films — Wick seems to have dozens. Everybody knows him, from beat cops and mechanics to club bouncers and hotel concierges.“Wick has so many friends in this world because, at the end of the day, he’s inherently a good man,” the screenwriter Michael Finch explained. “And he’s Keanu, so it’s very hard to dislike him.”That would be Keanu Reeves, who has played the franchise’s titular hero since the first Wick film in 2014. Now considered one of the greatest action films ever made, “John Wick” started a nearly $600 million franchise that has been praised for its imaginatively over-the-top action sequences. And over the years, Wick’s friend circle has only grown.“John Wick: Chapter 4,” the latest installment of the series directed by Chad Stahelski, premieres Friday, and features even more of Wick’s chums. The franchise has always drawn top talent for its supporting cast, like Halle Berry, Laurence Fishburne and Willem Dafoe, and this sequel is no different. Joining this time around are the martial arts film veterans Hiroyuki Sanada (“The Last Samurai,” “Ring”), playing a close friend from Wick’s distant past, and Donnie Yen (“Hero,” the “Ip Man” series), starring as a blind swordsman enlisted to kill Wick.John Wick’s universe includes Donnie Yen, center, as a blind swordsman and Scott Adkins as Killa.Murray Close/Lionsgate“We spent three movies showing how lethal John is,” the producer Basil Iwanyk said. “So we thought to ourselves, we’ve got to give him a nemesis that you believe he can’t beat.”For newcomers to the franchise, the setup is simple: Wick is a former assassin who has managed to get out of the business, only to be drawn back in by the rash actions of one very stupid guy who kills his dog, the last gift from his recently deceased wife, and steals his car. Wick comes out of retirement to murder the man, and thus our story, and the franchise, begins.Before long, we meet an ever-growing series of pals (present and former), acquaintances and longtime associates. In the first minutes of the original film, we meet Marcus, an old friend played by Dafoe. Not long after, a police officer, Jimmy (Thomas Sadoski), stops by because Wick’s neighbors are complaining that he’s been murdering people too loudly. “Evenin,’ John,” Jimmy greets him. Soon after, yet another friend, Charlie (David Patrick Kelly), comes to cart away all the corpses and mop up the blood. “Good to see you, John,” he says, doffing his cap.On a purely practical level, Wick’s many friends exist to infuse some humanity into this otherwise fearsome killer of men. “The action sequences are phenomenal,” said Caitlin G. Watt, the co-editor of “The Worlds of John Wick: The Year’s Work at the Continental Hotel,” an ambitious collection of academic essays. “But if you don’t like John Wick or sympathize with him, the movies don’t work.”The plethora of friends also provides a nod to the long and harrowing career Wick had before we first met him, including the legendary “impossible task” that allowed Wick to retire and burnished his reputation as the fearsome Baba Yaga. “Chad and Keanu created a character whose life you simply drop into,” Finch said. “You don’t know anything about what happened. We still don’t know what the impossible task was.”It’s largely through these friends that we learn about the very complex world Wick inhabits: its communication systems, rules of etiquette, international chain of deluxe hotels (the Continental, preferred lodging for the world’s most discriminating assassins), and currency. You certainly aren’t going to learn much about this through our taciturn hero, whose most impactful lines generally run only a few syllables long: “I’m going to need a gun,” for instance, or “Yeah.”To be fair, nobody wants a chatty Wick. “These action films about mythological, larger-than-life characters die when you ask your lead to be expositional,” Finch said.Watt, who has written about the franchise’s ties to Russian folklore, tales of knights in exile and the idea of the “monstrous hero,” agreed. “You don’t go to John Wick for the dialogue,” she said, adding that no one expects it “to be like a Noël Coward play. But the dialogue does a lot of work in establishing these characters, their relationships and this very strange world where all of this takes place.”As for just how many true friends Wick has: “I think there are Continentals in most major cities, so there are probably roads that lead to John wherever he goes,” the producer Erica Lee said. “I don’t think he’s the guy who has a surprise 60th birthday and there’s a room full of people. But he does have a select handful of trusted people he can call out to.”Halle Berry played — what else? — a former friend in “John Wick 3.”LionsgateBeginning with the first film, the creators pulled from their own circle of friends to cast Wick’s. Stahelski met Kelly when both were working on “The Crow,” the 1994 superhero film. “I was a new stunt guy and he was in the cast, and he took time to talk to me,” Stahelski said. “So when I needed a Charlie, he was in my head.” A similar thing happened with Randall Duk Kim, the doctor who patches up Wick’s wounds — Stahelski had worked with him on “The Matrix Reloaded.”The franchise’s Manhattan setting also played a role in casting. “We were so below the radar, just an independent movie that didn’t even have distribution,” Iwanyk said of the first film. “But we shot in New York City, and there are so many actors there. That’s how we got John Leguizamo, Bridget Moynahan, Lance Reddick,” who died March 17 at age 60 but played Charon, concierge of the New York Continental, owned by Winston (Ian McShane), in all four chapters.When the characters — and the film — hit, the creators kept many of them on for the sequels. Others soon followed. “When we were talking about ‘2,’ someone said, wouldn’t it be cool if we got Laurence Fishburne, so it would be like Neo and Morpheus?” Lee said of the actor who plays the Bowery King in three of the installments. Berry, who played Sofia Al-Azwar in “3,” asked Stahelski for a part before a script was even written.In this latest installment, friendship again plays a major role. Old friends return to protect Wick, or hunt him.But just how, when and why Wick befriended all of these people is still largely a mystery, even to the creators. For the most part, histories for the characters, even for Wick himself, were created on the fly, if at all. “We never wanted to get into John’s back story,” Iwanyk said. “You know these people have a shared experience with John, and you know it was something intense and often violent, but you don’t know what it is specifically.”Even so, the stories wouldn’t work without these characters. A John Wick movie sans friends? “I wouldn’t know how to tell that story,” Finch said. “There would not be a successful franchise without a Winston, without a Charon, without a Bowery King.”John Wick’s Friend CircleAnjelica Huston as what passes for a maternal presence in John Wick’s world.Niko Tavernise/LionsgateBeing friends with John Wick isn’t easy. Over the years, people who have helped out Wick have been sliced seven times with a sword (Laurence Fishburne); smothered and shot in the head (Clarke Peters); tortured, then killed (Willem Dafoe); and asked to resign from their places of business (Ian McShane). There are friends whom Wick has shot at (Claudia Gerini), and others who have fired on Wick (McShane, Halle Berry). There are still others who want to be pals with Wick (Shamier Anderson, Mark Dacascos), but they’ve been hired to assassinate him, which tends to sour things in Wickworld, but often not for long.With all the bullets flying, who can keep track? Here’s a quick primer to a handful of Wick’s friends.WINSTON (IAN MCSHANE) He is the owner of the New York Continental, a swanky hotel for assassins. The establishment’s primary rule: absolutely no killing on the premises. When Wick does, it puts him at odds with Winston and the High Table, the shadowy crime council that oversees the world’s Continentals. “Winston is empathetic toward John’s quest, but I think he’s always trying to guide him toward his better instincts and away from danger,” the screenwriter Shay Hatten said.CHARON (LANCE REDDICK) The trusty, resourceful concierge of the New York Continental, Charon gets arms and ammo for Wick, fights alongside him and even breaks hotel rules by taking care of his (second) dog when the assassin is away. Even so, Charon doesn’t seem all that broken up when Winston shoots Wick in the chest at the end of the third installment. “Charon is an inherently decent man,” Finch said. “But even the nicest guy in the series has an edge to him.”THE DOCTOR (RANDALL DUK KIM) Called upon to patch up Wick’s wounds, the Doctor takes a bullet for Wick — two, in fact, from Wick’s own gun, to cover up the fact that he is helping Wick against the direct rules of the High Table. “We excuse a lot of what John does because people like the Doctor, who are inherently OK and decent, seem to respond positively to him,” Finch said.THE DIRECTOR (ANJELICA HUSTON) The leader of the Ruska Roma, another crime organization, the Director was a maternal figure to the orphan Wick. For helping him escape punishment in “3,” the Director’s hands are ritually skewered by the High Table. “I wouldn’t call them friends, at this point,” Lee said. “I think she’s probably annoyed at John.”THE BOWERY KING (LAURENCE FISHBURNE) As the self-anointed sovereign over a network of seeming panhandlers and vagrants who act as his eyes and ears, the Bowery King is an invaluable source of intel for Wick, as well as a major supplier for Wick’s other needs. “The Bowery King is an anarchist,” Lee said. “So when John had to go off grid, he was there to help him get guns, supplies and bulletproof suits.” More