The Yon-Rogg. That one was a bit more easily guessed, of course.

This time round, the mystery is clearly the true identity of Taskmaster. In the comics, Taskmaster is a mercenary and assassin-for-hire who's gifted with the ability to mimic any action he sees; he's trained by watching skilled combatants such as Hawkeye, Captain America, Daredevil, and Shang-Chi. But Marvel Studios is carefully avoiding giving viewers more than the briefest of glimpses of Taskmaster, to the extent that viewers are speculating whether the MCU's Taskmaster is a woman rather than a man.

Related: Black Widow Trailer Breakdown: 23 Story Details & Secrets You Missed

But the Black Widow trailer offers some tantalizing clues. It subtly hints that Taskmaster has been active in the MCU for quite some time - and that he's encountered both Black Widow and Hawkeye before now.

Black Widow Is Returning To Natasha's Roots

Black Widow Red Room

According to MCU timeline has confirmed that all that came to an end in 1997, when Natasha wound up on SHIELD's radar in the worst possible way. Fortunately for Natasha, SHIELD assigned Hawkeye to take her out - and he made a completely different call.

The Red Guardian to their side. The trailer appears to show Natasha leading a mission to infiltrate and then destroy a remote facility - and the timing of the voice-over strongly suggests that viewers are meant to believe that this is the Red Room.

If Black Widow is going back to her roots, then it stands to reason that Natasha Romanoff also has a history with Taskmaster, given he's the villain of the Black Widow movie. Taskmaster's troops appear to be guarding the Red Room, which means he may well be the one who runs the Red Room - the literal Taskmaster of the Black Widows. Alternatively, it could well be that the Red Room trains both men and women, and that he's the one in charge of the male equivalents of the Black Widows.

Related: Black Widow Trailer Proves The Movie Is Years Too Late

The Black Widow Trailer May Hint At Taskmaster's Encountering Hawkeye

Black Widow Trailer Taskmaster With Bow

The Black Widow trailer does feature a couple of brief scenes with Taskmaster, and one of them shows him using a bow and arrow. While Taskmaster is a proficient archer in the comics, in truth this is quite an unusual weapon for him; he tends to prefer swords and staves for up-close-and-personal combat, and otherwise uses guns. So Marvel's clearly chosen to switch things up for a reason.

In the comics, Taskmaster has a photographic memory that allows him to perfectly imitate anything he's seen. Assuming the MCU's Taskmaster possesses the same ability, it's reasonable to assume he's learned archery from having seen someone else use a bow and arrow in combat. The most likely candidate is, of course, Hawkeye; the Avenger who redeemed Black Widow in the first place, who persuaded her to give up working as an assassin-for-hire and instead SHIELD. This single shot subtly teases the possibility that Taskmaster doesn't just have history with Natasha Romanoff; he's also crossed paths with Hawkeye as well.

Is This The Secret of Budapest?

Black Widow Budapest

Continuing the theme of going back to Natasha Romanoff's roots, Black Widow features a lot of action set in the city of Avengers: Endgame, the two shared a mission to the planet Vormir, and Hawkeye quipped about how they were "a long way from Budapest." That last reference was a particularly interesting one, because it seemed to imply that Clint Barton was referring to the place where they'd first met, and contrasting it with the cosmic scale of their journey's end.

If Black Widow's life is indeed coming full circle, then it's quite possible Budapest was the place where Hawkeye and Black Widow fought Taskmaster once before. If so, then the city must have devolved into a state of chaos during that last confrontation; after all, the Chitauri invasion of New York was what inspired Natasha Romanoff's first reference to Budapest. It's possible her memories were triggered simply by the fact that the pair were facing an army of faceless foes, who didn't care at all about collateral damage. That would fit with Taskmaster's clearly having soldiers of his own in the Black Widow trailer, relentless assassins who are even willing to engage in a freefall pursuit. This would further explain why Hawkeye realized that this particular Black Widow could be redeemed; presumably she worked to keep civilians and innocents out of the line of fire, just as she did in the Battle of New York.

While Black Widow is set shortly after the events of Captain America: Civil War, that doesn't necessarily mean it won't have flashbacks to Clint and Natasha's first meeting at Budapest. The trailer confirms at least one flashback sequence, with Marvel using their trademark de-aging technology on William Hurt to show a younger Thunderbolt Ross, so there could always be others. The truth about Budapest - and Taskmaster's connection to it - may be about to be revealed at last.

More: Black Widow Trailer Reveals Infinity War Connection