During the final episode of Hawkeye, one of the big reveals is that the watch that Clint Barton was looking at during the series is actually owned by his wife Laura, who was revealed to be a former agent of SHIELD named "Agent 19" (or "Mockingbird" in the comics). It was a surprise twist for some fans, but a welcomed one as it shows a significant development for the character.
Speaking with Marvel.com, director Rhys Thomas discussed the twist surrounding the character. "That's what's exciting about the Marvel Cinematic Universe," he said. "It's Marvel, and the comics are so deep. It's a universe. What I love is that these ideas could get introduced as we were sort of prepping the show."
He continued, "We've seen her over these years as his wife, and there was obviously a desire [to expand her backstory]. We should know more about her. There's more to her than just staying at home with the kids. It was a fun little thing to tease out over the season and again a nice little payoff that hopefully promises more of a character planted at the end.
Since her debut in Avengers: Age of Ultron up until the finale episode of Hawkeye, Laura was only seen as a wife of Clint, but the series started to give us clues that the character might be more than just a wife until they confirmed it in the finale. Now, we know that she was also an agent of SHIELD and she is also established as the MCU's Mockingbird. It also affirmed the theory that fans have been speculating prior to the finale.
However, there are fans who are also upset about the reveal since it further establishes that Agents of SHIELD is not canon to the MCU where Adrianne Palicki played Mockingbird in the series. With the appearance of the Darkhold in WandaVision and Laura Barton being established as the Mockingbird of the MCU, it does say that Agents of SHIELD is not part of the official MCU canon.
Either way, Laura Barton being revealed as Agent 19 is a welcomed twist for a lot of fans and, hopefully, we'll get to see her in action in the future.
All episodes of Hawkeye are currently streaming on Disney+.