Acausality (Type 5. Unbound by the flow of linear time across the Multiverse of Mundus. The nature of his Godhood makes it so that Vivec was simultaneously always a God, but also born a Mortal, giving him two contradictory, equally true pasts)
Type 5: Causality Transcendence: Characters with this type of Acausality transcend the normal boundaries of cause and effect, existing outside of the causality of a system. Even interacting with them normally may prove virtually impossible.
What this means is even with Yhwach's powers, even this souped-up Shrek would be unable to interact with him very meaningfully.
Not to mention, Precognition, High-Godly Regeneration, & a plethora of other powers.
Heck, AFAIK, Gods like Vivec in The Elder Scrolls, should be able to use their powers to control things like Causality, the Laws of nature, physics, & a plethora of other things.
Keep in mind, Causality, Law & Conceptual Manipulation are easily some of the most potent abilities you could have if you can freely use them, & Vivec can.
He can Causality Manip you to say the CAUSE of your power causes a different EFFECT. Like the CAUSE of you shooting a laser beam at him turns a nearby rock into a banana instead.
He can Law Manip to say that in the universe you're in, you can only move while speaking backwards.
Among a plethora of other possibilities.