A fairly classical progression story with its own unique elements which takes place in a multiverse containing countless inhabited worlds as well as smaller realms floating through the void between worlds. It is governed by a system containing the usual stats, skills, classes and tiers from G to S followed by Gods and Godkings, through which one can advance by gaining experience.
The most powerful beings in this world - the equivalent of ancients or primordials from other novels - are the sovereigns, distinguished by having a class with "sovereign" in its name. All such classes give their wielders unparalleled control over their aspect or element (fire, metal, strength etc.) and there can only be one sovereign of each type at a time. However, only around a dozen sovereigns have arisen throughout the ages in the multiverse due to the requirement of performing a feat of truly ridiculous proportions relative to your level related to the element in question.
However, as it eventually must given infinite time, something unexpected happened. An overlap of unlikely events that the system hadn't accounted for, resulting in an individual being offered the sovereign class not as a Godking, God or even S-grade but at their very first class selection at the start of G-grade. As if that isn't enough, this class is unlike any that came before: Our protagonist had met the requirements for not one, but two sovereign classes. And so as his power and skills grow with every grade he advances, we follow the rise of the Voidsoul Sovereign.
[Details for world building and the backstory of how our protagonist unwittingly met the requirements for his class will be added to this chapter soon]