The following contains major spoilers for Avengers #64, available now from Marvel Comics.
Ever since their first appearance, the Multiversal Masters of Evil have proven themselves to be some of the most powerful villains of all time. As terrifying as any individual member of the team might be, Doom Supreme stands above them all in terms of sheer destructive ability. Now that the Avengers are upon him, Doom Supreme has taken the opportunity to unleash what might be his greatest weapon, and it just so happens to be one that nearly destroyed the Marvel Universe once already.
While Mephisto and the Council of Red launch an all-out assault on Avengers Tower, all but one of the Multiversal Masters of Evil face off against the modern day and Stone Age Avengers. As seen in the pages of Avengers #64 (by Jason Aaron, Javier Garrón, David Curiel, and VC's Cory Petit), Doom Supreme has taken the opportunity to watch from afar as his fellow villains are cut down. Unsurprisingly, their losses mean nothing to Doom Supreme. Not only does he still have an army of variants to send into battle, but they are also charging in on an entire planet made by Doom.
Doom Supreme Weaponized Marvel's Most Dangerous World
There isn't any telling what corner of the multiverse Doom's largest counterpart hails from, although that hardly matters given that it is a living planet both bearing the villain's visage and chanting his name. Despite not making any previous appearances, this clear amalgamation of Doom and Ego the Living Planet is more than just a means by which to deliver an army, but a nearly unstoppable force in its own right. Ego was well established as an impossibly powerful being as early as his first appearance in 1966's Thor #132 (by Stan Lee and Jack Kirby), and the years since have proven as much more than once.
On his own, Ego has taken on the likes of Galactus, the Silver Surfer, and his own twisted brother. He hasn't won all of these battles entirely on his own, but they have served to cement what Ego is capable of. Even those that went fatally wrong for Ego have only made him seem stronger, as the Living Planet has miraculously returned to life following every subsequent destruction. In fact, the most recent of these gave Ego a chance to fight for the fate of the multiverse during the Reckoning War, while the death that preceded it gave another villain the chance to push the limits of what Ego can do.
Ego May Start a New Trend in the Marvel Universe
2021's "The Last Annihilation" saw Ego undergo a monstrous transformation not all that unlike the one who embodies Doom has been through. After being encased in an impenetrable shell, the primary Marvel Universe's Ego emerged as a cragged, burning version of himself entirely possessed by the Dread Dormammu. This gave Dormammu a massive advantage in the cosmic war that was unfolding.
A handful of instances of this very particular occurrence isn't enough to safely call it a trope, but it is safe to say that this might be the beginning of a new trend in the world of Marvel Comics. Then again, major events just keep getting bigger, and with Ego being about as big as it gets in terms of familiar faces, he is a prime target for getting the mash-up treatment in similarly massive stories. Considering how unlikely it is that those are going away anytime soon, Marvel's next Ego could be right around the corner.