SPOILER WARNING: This article contains spoilers for "Uncanny Avengers" #13, which is on sale now.
"Uncanny Avengers" #13 sees the Avengers Unity Squad jump into the "Civil War II" action with a pair of stories showing how the mutant/superhuman/Inhuman team has coped with what we've seen happen so far. The first half of the issue from Gerry Duggan and Ryan Stegman jumps back to Bruce Banner's death in July's "Civil War II" #3. The first 13 pages of the issue show Deadpool's response to that action and prominently feature Hawkeye, showing the role the Merc with a Mouth played in-between issues of the main "Civil War II" series.
The rest of the issue sets up what will most likely (judging by future "Uncanny Avengers" covers) constitute the main thrust of "Uncanny Avengers'" "Civil War II" tie-in. We jump to New Attilan where Medusa escorts Captain America (the HYDRA-loyal Steve Rogers) to the quarters of the precognitive Ulysses. The Inhuman has made a prediction about Steve Rogers' team, pinning one of them as a potential source of trouble.
Ulysses warns Captain America that Cable is "keeping the wrong company" and that the mutants "will wage a war." It's possible that Ulysses' latter comment is referring to the upcoming "Inhumans vs. X-Men" series; the former comment refers to what we see in the next few pages.
Later, Steve Rogers confronts Cable as the time-traveling mutant prepares to board a personal plane. Rogers tells Cable about Ulysses vision, and Cable retorts, "Let's grab a bite when I'm back in town and we can talk about who knows what about the future." Reminder, Cable just returned from a point in the near future earlier in this series; it's entirely possible that on his jaunt forward in time, he learned all about Steve's HYDRA influence. Cap suspects as much, asking Cable what he meant by that comment.
Cable shoves past Cap and boards his plane, revealing that he's not alone on this mystery mission.
Rogue and Cable have split off from the Avengers Unity Squad to address the very real threat posed by the Terrigen Mist, which is also currently poisoning Rogue. But Cable and Rogue aren't the only two mutants on this mission. The Avengers members turn to the cargo hold and greet their unlikely allies...
...Sebastian Shaw and Toad. Both characters are longstanding enemies of the X-Men. Shaw is most known as the Black King of the Hellfire Club, the group partly responsible for unleashing Dark Phoenix on the universe. Toad is one of the X-Men's oldest enemies and an original member of the Brotherhood of Evil Mutants. Toad's been a fairly consistent presence in the X-books over the past few years; he reformed and served as the janitor for the Jean Grey School, but more recently fell back into his villainous habits by kidnapping and nearly killing the teenage Cyclops in "All-New X-Men."
Shaw's been in limbo for a bit longer than that, though. He did have a brief speaking cameo in this year's "Uncanny X-Men" #6 and also popped up for a second in "Mighty Thor" #8, but you have to go back four years to find the last time he played a major role in a storyline. In 2012, he was an antagonist for a story spanning "Avengers Academy" #29-31.
We'll get to see how this uneasy alliance plays out when "Uncanny Avengers" #14 arrives in stores on September 14.