Hercules solos. Regular Namor would probably lose, but he would make them work for it.
People are giving Invincible characters way too much credit. I've read every single Invincible comic and all of their feats put them at the low herald level at best. The only outlier is Omni-Man going even with Supreme... but that's really not enough to negate all of their actual limitations: dying upon colliding with the surface of a planet, burning to death at the surface of the sun and so on.
So true. Remove Supreme from ever meeting a Viltrumite, and you're left with possibly Wonder Man level characters. Thragg the most powerful of them, died from the heat of a star. This is not something that would kill Supreme. They were also overall too squishy to place them at High Herald levels. How could these guys get so much credit, while He-Man is stuck in the minor leagues?
The Werewolf would die if he drank a glass of Ionic Silver, Superman would die if he wore Kryptonite pajamas, etc. Fire is Namor's weakness, whereas the entire Invincible Universe is filled to the brim with characters that have no reason to be as squishy as they are.
Wonder Man is below Namor in my opinion. I base it on how well they've done in similar situations.
Sentry and Hulk absolutely are squishy. They are hyper durable with a very, very strong healing factor as their main defensive tool. The same applies for Invincible. And even if I'm generous enough to say that he is slightly more hyper durable than them (which he isn't), his healing factor doesn't even come close to theirs. Damage they heal in seconds, he needs months to heal. And unlike them he can't even regrow limbs. Kill them and they come back; kill Invincible and he is a goner.
(Yeah, I know that Sentry didn't come back in King in Black, but that looks like a "fuvk your immortality, I want to you in my on-going Thor run"-moment (as teased by Donny Cates).)
Superman, Thor and Hercules have actual invulnerability with minor, minor healing factors. And in my mind Invincible punching someone like Hercules over and over again would ultimately result in him shattering his own hands and his head, if he resorts to headbutting. The power level difference between those two is that vast, when Hercules is on point.
I'll keep repeating it: Invincibles GREATEST feat of power was destroying a planet. But... destroying that planet was a shared feat with two other Viltrumites and they still required additional help from Space Racers rather powerful gun, which had to destabilize the core of the planet first. If it didn't, they would have died upon impact.
Invincible isn't even close to planetary, where Hercules has performed rather well against +planetary level characters like Thor and Hulk.
Of course it could be that, but I don't recall any impressive feat from the viltrumites. Characters in the Invincible universe mostly scale off of each other, DBZ style.
Then again there's the planet feat in the War, though.
For example, the only 'damage' Nolan sustained during his fight with Supreme(which Kirkman himself states is canon), was a small amount of blood flinging out of his mouth toward the beginning of the brawl. Aside from that, he appeared completely uninjured(physically) -- even soaking Supreme's HV without skipping a beat. And mind you, this was arguably the most powerful/bloodlusted Supreme that we have ever seen.
Point being: Kirkman loves writing graphic, gore-filled fights that you'd almost never see in Marvel/DC. But as demonstrated by the [canon] fight with Supreme: that doesn't mean any cl.100 brick outside the Invincible-verse can just waltz up and rip a noteworthy Viltrumite apart.