Episode 8 of What If...? was arguably one of the best yet. The episode, which asked "What If...Ultron won?" showed the synthezoid at a level of power fans had never seen. He easily defeated Thanos, claimed all six Infinity Stones, destroyed all life in the universe, and became aware of both the Watcher, Uatu, and the multiverse.
With Ultron's eyes firmly set on spreading his genocidal conquest across every possible reality, Uatu has turned to the fallen Doctor Strange for help, in violation of his oath to not interfere. A cataclysmic showdown is brewing, as Uatu will almost certainly need more allies if he's to take down the newly all-seeing Ultron.
A question some viewers might have, though, is where are Loki's TVA and Kang in all this? Their whole deal was preventing a multiverse from occurring in the first place, so how was Ultron able to discover other realities? How was Uatu able to view any alternate worlds if the TVA pruned them before they could exist?
Let's dive into these questions a little deeper and find out exactly how What If...? fits into the wider MCU narrative.
An Infinite Multiverse and a Sacred Timeline
Firstly, let's get the meta-discussion out of the way. Outside of the MCU, in our reality where all the decisions are made, there simply wasn't the kind of interaction between the teams behind What If...? and Loki necessary to make any sort of cross-references. As previously reported, A.C. Bradley, head writer for What If...?, said that team was "already in deep development and writing the show by the time Loki got up and running."
In short, What If...? was already set in stone before there was a clear picture of where Loki would go and what it would touch on. That doesn't, however, mean that there isn't an in-universe explanation for the TVA's absence from What If...?, and this is where things get fun. Remember, the Sacred Timeline created by He Who Remains operated as though it were the only timeline. That was a critical part of the TVA's propaganda, but—like so much else about the TVA—it was all a lie.
The Sacred Timeline wasn't, in fact, the only timeline in existence. Rather, it was one separated from the others, with any diverging branches pruned before they could hit the "red line," which represented the point past which a timeline was capable of interacting with the rest of the multiverse and could no longer be simply reset.
The multiverse as it appears in What If...? and future projects like Spider-Man: No Way Home and Doctor Strange in the Multiverse of Madness always existed side-by-side with the Sacred Timeline seen in Loki. The true purpose of the TVA was never, in fact, to prevent the creation of a multiverse but rather to keep one thread of an existing one from joining a larger tapestry. But why?
It's All Coming Up Kang
The Sacred Timeline was forged by He Who Remains under the pretenses of preventing a multiversal war. While there's truth to that, the more specific reason behind the existence of the TVA and the Sacred Timeline was to prevent possible manifestations of Kang from wreaking havoc. The Sacred Timeline was almost certainly created in such a way that it completely separated out the existence of Nathaniel Richards/Immortus/He Who Remains/Kang the Conqueror from the wider multiverse.
Once that task was completed, the TVA's mission was set: prevent any manifestations of the Kang-entity from escaping the confines of the Sacred Timeline. In essence, that entire universe was a prison built by He Who Remains to contain himself, and the TVA was the legion of time-traveling jailors who ensured he stayed in his cell. So long as the Kang-entity remained confined to the Sacred Timeline, the rest of the multiverse was of no consequence: the only being in existence that He Who Remains feared was himself, not Ultron, not Thanos, not Galactus.
To be clear: the theory here is that no version of Kang exists in the multiverse glimpsed in What If...?. This operates under two assumptions: firstly, that the Sacred Timeline was simply an isolated branch of the multiverse kept separate from the rest by the TVA, and secondly, that He Who Remains would not allow any versions of the Kang-entity to exist outside of the Sacred Timeline because there'd be no point in its existence otherwise.
On Ultron, Kang, & Multiversal Destruction
It's unclear whether He Who Remains was aware of the goings-on in the wider multiverse to the point where he'd be aware of Infinity Ultron's crusade across the timeways. Even if he was, he wouldn't care. To him, Kang is the only individual in the history of any universe worth being concerned about, and up until Sylvie plunged her blade into his chest, that person was contained in the Sacred Timeline.
Now that He Who Remains is dead and the Sacred Timeline is spiraling into the multiverse, there is an infinite number of Kangs bound to spring up across infinite realities, i.e. the exact thing He Who Remains was hoping to prevent. However, even what should be perceived as a failure didn't seem to upset him overly much. Indeed, He Who Remains seemed certain that there were only two outcomes to his meeting with Sylvie and Loki: either they took his place as Kang's jailors or the infinite spawning of new Kangs would eventually create another He Who Remains who would eventually bring back order and establish another Sacred Timeline.
To He Who Remains, time is cyclical and always will be. He'll always win in the end, it's only a matter of the blood, sweat, and tears needed to reach that end. Pruning the timelines was the lesser evil on the grand scale, as maintaining a single, isolated timeline would always be less bloody than a multiversal war led by countless other versions of himself; the man he reckons to be the most cunning, cruel, and powerful one in all existence.
Now Cometh the Conqueror
There we have it: the TVA doesn't interfere against Ultron or any of the events in What If...? because they're just as confined to the pocket of the Sacred Timeline as Kang is meant to be. They have no jurisdiction outside the red line and into the wider multiverse, and they were never intended to. At least, that's how things used to be.
Now, the Sacred Timeline is undone. Kang is free, and every possible version of him will be rocketing across the multiverse to stake their claims on the ultimate prize: control of all time and space. While the destruction Ultron has unleashed in What If...? has been catastrophic, it pales in comparison to what is to come.
While fans will certainly be eager to see the Conqueror in action, they'll have to wait a bit longer. It's extremely unlikely that there will be any mention of or reference to him in Season 1 of What If...?. His appearance will be saved for future live-action projects like Loki Season 2, Doctor Strange in the Multiverse of Madness, and Ant-Man and the Wasp: Quantumania, just to name a few.