Thor's New Power Upgrade Officially Dwarfs Marvel's Most Powerful Hero
WARNING: Spoilers for Thor #23 ahead!
The recent massive power upgrade bestowed upon Thor by his father Odin, which he used to destroy the villainous God of Hammers, has elevated him beyond Marvel Comics "most powerful hero," the complex character the Sentry. While the Sentry is often described as having the "power of a million exploding suns," Thor's new All-Father Odinforce abilities are described as "the heat of a billion suns," meaning that Thor is literally at least 1,000 times more powerful than the Sentry.
The Sentry is a cosmic-level character with vast powers, and serious mental health issues, who has ranked as the most purely powerful Marvel superhero for many years, even if he is not always willing or able to use his powers. Not only does he describe himself as having the power of "a million exploding suns," but Marvel characters with genius-level intellects like Reed Richards and Tony Stark have also used this specific wording to describe his cosmic power level, confirming that this is not just an exaggerated explanation of his massive powers, but a literal unit of measurement that Marvel scientists use. If any Marvel character is going to rival this power, and also not exaggerate about their strength, it is the Asgardian God Thor who is just as cosmic as the Sentry.
In Thor #23—written by Donny Cates with art by Nic Klein and Matt Wilson—All-Father Thor has gained the power of the Odinforce, given to him in totality by his father Odin after he sacrifices his life so that Thor can defeat the God of Hammers. Thor is able to, rather easily, defeat the Mjölnir-Mangog being after obtaining the Odinforce powers, and destroys the entity while in the cosmic forge Nidavellir, claiming that the power he is wielding is equal to "the heat of a billion suns." Odin used this power and the spirit of the God Tempest to form Mjölnir, the most powerful weapon in history, so it is only right that Thor was able to withstand and control this massive power to take down the God of Hammers and destroy his beloved hammer, formally bringing his power level about that of the Sentry and establishing him as Marvel's strongest hero in current continuity.
The use of the phrase "heat of a billion suns" seems to be very targeted, both by Thor and by the writer Donny Cates, who has also written stories using the Sentry in the recent past. Both Thor and the Sentry have powers that exist on a cosmic, primordial scale, so it only makes sense that the language used to describe them would need to be contextualized in the power of multitudes of suns and there would be no point in either hero exaggerating their power levels. During the King in Black event, which Donny Cates was a lead writer on, Cates used the Sentry in a major way in a bid by the heroes to defeat Knull, meaning that he is very well versed in the Sentry's power level, and the phrasing around how that level is gauged. If Thor's new power is to use the power of a billion suns, that means at baseline he is 1,000 times as powerful than the Sentry is.
In Eternals #10, in the lead up to the "A.X.E. Judgment Day" event, the Eternals files on the Avengers are shown and All-Father Thor is referred to as, "An 'All-Father' class god-being in an adolescent stage" meaning that the upgrade he has just displayed against the God of Hammers is potentially just a fraction of his true power. To see Thor's upgrade into an "All-Father class god-being" make sure to read Thor #23 and compare his power against the infamous Sentry for yourself.