How buff are heralds of Galactus?

Just how powerful are heralds of Galactus?  As seen in a prior post, Nova, an inexperienced and fresh herald, was able to pretty much destroy the vast majority of the Skrull planetary defense fleet without so much as breaking a sweat, which makes sense because space is cold and heralds... don't sweat.  Ha, almost got me there.  

In the Silver Age of Marvel, we encountered our first herald in the form of the Silver Surfer, who did a pretty good job inspiring at least a little awe and terror in the hearts of us Earth folk, who I suppose had only really experienced powerhouses the level of Thor, and in conscious memory, only recently.  Speaking of Goldilocks, as Thing names him, Thor is an excellent way to test a situation.  This brings us to another herald, Firelord:

As you can see, he has no problem whacking Mjolnir away, and even less of a problem standing toe to toe with the Thunder God:

This is not to say that they can't be humbled with a little effort.  Thor has certainly given Firelord some shots back, and then some.  

To put them out usually takes a bit more than a college try, however, and someone with some juice on the level of the Big G, the guy who gave them their power in the first place.  While heralds have been humbled before, a good point of reference for what sort of being can do such a thing would be Jeanix, from Uncanny X-men vol. 1, no. 105:

Jeanix has always been a hard one to understand in terms of just what exactly constitutes her/its being.  During this era of the story, Jean was seemingly transformed into the Phoenix, something later retold as being replaced by her, with the unfolding of the story later being that there was indeed a shared consciousness between them.  In any event, when she was telling Firelord to fuck off and stop wrecking Misty Knight's apartment, my interpretation of her level of being at said juncture would be something of an incarnation of the two together, or the Phoenix made flesh.  Just a few issues later, she is able to be taken out by some strong knock out gas, perhaps something of a self-limitation of the Phoenix Force trying to understand the corporeal body it was now managing.  In any event, I am sure I am going to be coming back to that particular topic throughout the blog, as Jeanix is perhaps the most interesting object of questions regarding incarnations, avatars, and being.  My point here is that heralds are powerful, but not nearly on the level as their master or the other comic entities, abstract or otherwise.  

Now, as much fun as it is nerding out over power levels as if we were having a debate that descends into name calling faster than most arguments on the superheroes subreddit, a.k.a "the answer is always Darkseid is stronger than anything else ever",  I maintain that there is a far more important question.  Just how "mortal" are heralds?  

By the point this bit of dialogue happens during Fantastic Four vol. 1 issue 49, Norrin Radd had been the Silver Surfer for at least a century, if not for several.  At first he retained his conscious experience of being a mere mortal, but as he started having difficulty finding uninhabited worlds for Big G, the Devourer decided to do a little psychic alteration on Norrin to get rid of his compassion.  Now, Galactus is not a complete douchebag, arguably a force of nature beyond being either a stand up guy or a douchebag, and knowing that Norrin would one day leave his service behind, well, he didn't exactly perform an irreversible lobotomy.  Alicia Masters there was able to awaken his inner decency and mortal experience and go back to being a bit of Norrin again.  Our friend Firelord, otherwise known as Pyreus Kril, is no different in this regard.  They are very much mortals in terms of soul, albeit with powers and transformed physical being that amounts to something of a minor deity/cosmic being.  Even centuries into it and recovering from his psychic alteration, Norrin sees the universe with expanded, but still very mortal eyes.  Like mortals in general, this does not mean that all heralds are heroes.  Terrax, for one, is a bit rough around the edges if not downright evil.  Terrax the terrible, Terrax the dickhead, Terrax the turd.  As Team America: World Police elegantly puts it, however, sometimes you need a dick to fuck an asshole:

Heralds are definitely their own entity, and can be best described as man becoming cosmic/divine, and where they end up with that newfound aspect is up to them.  They are definitely in a unique position where they can redefine themselves into something of a new state of being and transcend their mortal souls, but often do not chase that ambition.  Norrin admits that he has very lofty goals, but still... wants to be himself.

Before we part ways, as an additional note, not all heralds come from places of mortal origin, but they often are.