When the Avengers: Endgame trailer first hit, fans saw a team of heroes shattered by their loss to Thanos. Black Widow, Captain America and Thor were all devastated, but Clint Barton was beyond the pale. While some fans recognized Barton’s new Endgame look from Brian Michael Bendis’ New Avengers run in 2005, others were surprised when they first got a look of who Clint had become: the ninja-like vigilante Ronin.
**Spoiler Warning: There are spoilers ahead for Avengers: Endgame**
If you have seen the Endgame already, then you know that Clint basically drops off the map after the snap. Left shattered by the loss of his family and the inability to do anything to change the outcome, he seemingly loses all sense of right and wrong. We don’t hear from Clint until the second act when Black Widow is running an Avengers team meeting.
In that scene, Rhodey, aka War Machine, reports that someone, most likely Clint, has been murdering cartel gang members in Mexico. A short time later, we finally get a look at Ronin, who gleefully and savagely dispatches an entire cadre of Yakuza in the rain. He tells them something along the lines of “you may have survived the snap, but you’ll never survive me.”
From his debut in Marvel’s The Avengers in 2011, Clint has been portrayed as a former mercenary with a sarcastic streak and a heart of gold. Drawing from versions of the character in the Ultimate Comics as well as his ample time with the Avengers, Hawkeye wasn’t given much of a backstory until Avengers: Age of Ultron and Captain America: Civil War, when we saw the gentler side of Clint. He's a caring father, loves a family, and his best friend is Black Widow. So when we see a revenge-obsessed Clint, taking out his post-snap aggression on bad guys around the world, it seems very jarring.
But who are these people? What did they do Clint Barton? And why is he killing them? To answer the question, we have to go back a bit.
There’s no mention of Clint’ past work as a mercenary or of his time with S.H.I.E.L.D in Mexico and/or Japan in any of the Marvel movies. We hear about Budapest, but there's little else. Therefore, we can only assume the screenwriters tapped directly into Bendis’ New Avengers to inform Clint's onscreen journey in Endgame.
Ronin first appeared in New Avengers #11, in which Bendis tapped Maya Lopez aka Echo to become the mysterious ninja. In that arc, we first see the character taking out a gang of Yakuza in Toyko. Later, Ronin is recruited by Captain America via Daredevil to infiltrate the evil Hand clan after they and Madame Hydra kidnap the Silver Samurai.
Hawkeye doesn't actually take on the role until New Avengers #27, when the Avengers rescue Lopez from the Hand. Using the backdrop of Toyko, Bendis pits the Avengers and Ronin against an unending army of ninjas and bad guys. Six issues later, when Clint tries to hand back the costume and Ronin identity to Lopez, she declines and Clint becomes Ronin full-time.
Much like in Endgame, when Clint dons the Ronin costume in the comic books, he ditches the bow and arrow for a samurai sword. In addition, he also wields a set of slightly less deadly nunchucks.
The name "Ronin" refers to the Japanese term for a masterless samurai, a lone warrior and that’s exactly what Clint is in the movie. He’s a man who’s lost everything and with nothing to live for, he focuses on the people he thinks don’t deserve to have survived the snap. As for the criminals he targets in the movies, it seems to be completely discretionary. While we hear that Ronin is actively murdering people in Mexico we never see it. The only shots of Ronin in action happen in Japan, where he faces off against the Yakuza much like the comic books.
Whether the bad guys Ronin kills in Endgame are meant to be the Hand or just some day to day gangsters is yet to be seen.