The following contains major spoilers for Avengers Beyond #1, on sale now from Marvel Comics.
While the Avengers have always had a plethora of astonishing forces to face off against, few if any have sent them spiraling into uncharted territory like the incredibly powerful Beyonder. Over the years and across multiple iterations of reality, the Beyonder has proven time and time again that he is a greater force than almost any in the Marvel Universe. This makes it all the more surprising that he has come looking to Earth's Mightiest Heroes for help. Unfortunately, the time they have to do so is quickly running out not just because of the terrifying new foe they have yet to meet, but because the Black Order is preparing to make a lethal comeback ahead of their new master's arrival.
The assembled heroes of Avengers Beyond #1 (by Derek Landy, Greg Land, Jay Leisten, Frank D'Armata, and VC's Cory Petit) find themselves face to face with the all-powerful Beyonder who, shockingly, has come to them for protection. As the Beyonder explains, the true source of his people's powers (an even more powerful being known as the Lost One) has been freed from his extradimensional prison. Now the Lost One has begun hunting the cosmic race across every corner of reality. Thankfully, the Beyonder knows that there is no threat that Earth's Mightiest Heroes aren't equipped to handle, although the impending arrival of the Black Order is sure to challenge that notion.
The MCU's Black Order Has Returned to Terrorize the Avengers
First seen in 2013's New Avengers #8 (by Jonathan Hickman and Mike Deodato), the Black Order traditionally serve as Thanos' generals, hand selected by the Mad Titan from the darkest corners of the Marvel Universe. Although these villains might have been made most famous thanks to their appearances in the MCU, the Black Order have made just as much of a name for themselves in the comics. Comprised of the menacing Black Dwarf, Ebony Maw, Proxima Midnight, Black Swan, and Corvus Glaive, the Black Order have stood against the Avengers on several occasions, although they have never been able to truly overcome the heroes' combined might.
While the Black Order have suffered plenty of defeats of their own, those failures haven't stopped them in the pursuit of fulfilling the Mad Titan's desires. However, Thanos' supposed demise left them without a leader to follow. Corvus Glaive may still be trying to carry out his master's orders in his search for the Black Infinity Stone, but the others have largely been left out of the recent spotlight - until now.
The Black Order's New Master Makes Them Even Worse
Assuming the Black Order are aware of the goings-on regarding the Beyonders and the Lost One, it will only be a matter of time before they have unleashed a torrent of terror upon Earth's Mightiest Heroes and the overall Marvel Universe. Thanos was certainly a formidable master, but he pales in comparison to the threat posed by the Lost One.
Regardless, it is unknown whether the Order is working in service of the Lost One or carrying out the orders of some other unseen master. The addition of another faction (or even a resurrected Thanos) would surely complicate matters further, especially if it forces the heroes to wage a war across multiple fronts. Considering what the Avengers are already facing, the specifics of their upcoming encounter with the Black Order may not matter as much as the ability of Earth's heroes to survive the pending conflict.