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human
[MARVEL: What If] Is Ultron the most powerful being in the known Universe(s) now? If so, how can Dr. Strange contain him within the collapsed Universe?

Absolutely loved this series but these two questions loomed large for me at the end.

I don't quite understand how Ultron can be more powerful than a cosmic being, like the Watcher...and Dr. Strange still have the ability to hold him hostage in his collapsed Universe. I understand Strange consumed all those beings to gain immense power but does that mean he's "technically" the most powerful?

Are both more powerful then any known cosmic being, ie: The Living Tribunal, Beyonder or The One Above All?

If not, where would you rank them?

If not, why haven't any of the more powerful beings stepped in to stop Ultron? Is that answer as simple as, Marvel isn't ready to introduce them to the MCU?

I apologize for the thousand questions but these need answered,  lol.
gpt
Your first question is that Strange wasn't holding Infinity Ultron hostage in the collapsed universe. He was holding Ultron in the collapsed universe. Ultron and Kilmonger had equal pull for the Infinity Stones, and while the stones were being pulled between them, neither had their power. So Ultron and Kilmonger was stuck in a never-ending battle for the stones. (Presumably they were trapped in some manner of stasis by Strange's magic because otherwise Kilmonger would eventually tire and Ultron would recover the stones.)

Your second question is more difficult to answer though because we haven't seen the Living Tribunal, Beyonder, One Above All, etc. in the MCU, and the MCU regularly changes the power levels of characters from their comic counterparts. So right now it's impossible to know how Infinity Ultron stacks up against those characters. We just know that he was at least as powerful as the Watcher.

As for your last question, that's also unclear. We know Eternity didn't step in because he was locked away in another dimension. It's possible the others were locked away as well or have other oaths of non-interference for some reason or another. The MCU will probably explain that eventually, but we likely won't get that answer before The Kang Dynasty or Secret Wars at the earliest.