Since Disney acquired 21st Century Fox, Marvel Cinematic Universe fans have been waiting to see how the many beloved Marvel characters that Fox had held the film rights to will be adapted on screen. Ms. Marvel surprised audiences with the revelation that Kamala Khan is the MCU's first mutant and set the stage for the arrival of the X-Men. However, there has been no indication of how the franchise will introduce the team's long-time co-star, Deadpool.
With Deadpool 3 already confirmed and set to take place within the MCU, it's only a matter of when and how the Merc with the Mouth will make his long-awaited debut. While Deadpool's entry may end up being a straightforward one, there is a blueprint for a more creative and appropriately "meta" introduction in the form of Agent X. This obscure character served as the cornerstone in one of the Regenerating Degenerate's most self-aware storylines.
During the early 2000s, the sales of the long-running Deadpool series had reached unprecedented lows, and numerous attempts to revitalize them had failed. Eventually, Marvel Comics' leadership chose to end the series with one final storyline before rebooting it from issue #1 with a new "X-themed" title to link it to the larger X-Men franchise and hopefully, boost sales. However, instead of giving Deadpool a new identity to reflect the upcoming series' title and tone, incoming writer and industry veteran Gail Simone decided to play with the readers' expectations by embracing the Merc with the Mouth's self-referential nature.
Agent X, aka Nijo, was first introduced in Deadpool #65 (by Gail Simon, Udon Productions, and David Sharpe), the final issue of the series, as the right-hand man of the psychic mutant mercenary, Black Swan. Believing that Deadpool had murdered his brother, one of the heads of a yakuza organization known as the Four Winds, Nijo assisted Black Swan in a plan to torture and kill the Merc with a Mouth. During the final battle against Deadpool in Black Swan's German estate, however, Nijo discovered that Black Swan was the one who killed his brother and that he wanted revenge on Deadpool for stealing credit for his kill. Soon afterward, Deadpool detonated a powerful bomb that seemingly killed everyone -- including himself.
In Agent X #1 (by Gail Simon, Alvin Lee, Rob Ross, Udon Studios, Pierre Theriault, and David Sharpe), which was set immediately after Deadpool #65, an amnesiac man known as Alex Hayden with a personality and skill set eerily similar to Deadpool's emerged in New York City, intent on becoming the greatest mercenary in the world. After meeting up with Deadpool's former secretary Sandi Brandenberg, Alex formed a mercenary company known as Agency X alongside her, Taskmaster, and Deadpool's mercenary acquaintance Outlaw.
Throughout its 15-issue run, Agent X heavily implied that Alex was Deadpool in disguise, although the character himself repeatedly insisted that he wasn't the Merc with the Mouth. With many other concurrent Marvel properties ditching their colorful aesthetic and over-the-top spectacle for a more "grounded" style, Agent X was a breath of fresh air, portraying Alex as a self-aware parody of the more "serious" direction that Marvel was trying to take itself in. Unfortunately, while Agent X was well-received by critics, this new direction failed to attract new readers, and the comic's sales quickly dropped to the same lows they'd been at before the re-branding.
After a prolonged creative conflict with Marvel's editorial team, Simone left the series, forcing Marvel to hand it over to several fill-in writers as its sales continued to plummet, resulting in its cancelation. However, following the unexpected success of Fabian Nicieza and Reilly Brown's Cable & Deadpool, Simone was permitted to return and finish Agent X's storyline the way she'd originally intended. In Agent X's final three-part storyline, Black Swan returned with a catatonic Deadpool and revealed that Alex had always been Nijo, who'd received his personality and healing factor after Black Swan failed to steal the latter for himself. Following a final climatic battle against Black Swan, Deadpool and Nijo took back their true identities and parted ways as friends.
Following the cancelation of Agent X, Nijo would continue to make sporadic appearances as a supporting character for Deadpool. During one particularly humiliating outing, he was captured by HYDRA, who infected him with the obesity-causing "American Gene," forcing Deadpool and his long-time ally and agent of HYDRA, Bob, to save him. Later, Nijo went to live on Krakoa, revealing that he was a mutant all along.
While Agent X's prominence within the Marvel Universe has diminished, his history with Deadpool could make for a unique introduction to the MCU. Given the two preceding Deadpool films' penchant for fourth-wall breaking, Deadpool debuting as Agent X could be an effective way to establish the Merc with the Mouth's humor while paying tribute to a little-known but pivotal figure in the Regenerating Degenerate's history.