OK superman easily destroys the last dragonborn nothing can refute that but I'll scale the last dragonborns power though:
When scaling the dragonborns power one shouldn't use gameplay as gameplay isn't Canon to the lore or else we would have infinite damage and health dragonborn or dragonborn who can be easily taken by wolves; here's the evidence:
Of course, it had to be a TES story, so I was constrained by lore -- although not, interestingly, by game mechanics. I was told specifically that no one wanted to "hear the dice rolling" so to speak. We are to imagine the world of TES to be a real place, of which the games are merely representations. My book represents that world in another way
Elder scrolls games don't have damage feats due to it causing game problems such as destroying maps or messing with NPC's who give quests here's the evidence:
Todd Howard: Systemically destroying our spaces is something we have not found a good way to handle yet, because it’s so dynamic. We’re dealing with places that we have NPCs living, and providing quests and other game services. It’s something we avoid in every game unless we can specifically wipe it off the map, like Megaton
http://elderscrolls.wikia.com/wiki/User_blog:Kacj321/Skyrim_Fan_Interview
Elder Scrolls as a game has been limited to what they show in the gameplay as it would be to expensive to make it more lore appropriate and lack the required technology:
Wawro: Hm, I wonder, you gave us the hot tip before we started that it would be wise to sort of expand the boundaries of a new Oblivion playthrough by opening up everything, looking at the game and opening up the Oblivion gates as well. Is there an area you would suggest that well shows off what you’re talking about here? Maybe it shows your hand directly or the hand of a designer you admire?
Rolston: Uh, no, because the possibility of a lead designer knowing the content of any Elder Scrolls game is diminishingly small. Morrowind is the only one I can really talk about, but I don’t think I’d actually played more than 60% of the built content when we released the game. I had certainly played it in prototype or white box or things like that, but you just cannot play the whole content, it’s just too big to put the iterations into it. So the reason I suggested wandering to different places, just be a tourist.
Francis: I’ll springboard off of Alex’s observation to ask, Ken, you mentioned earlier when you were writing that bible for Morrowind, you were starting to write about all the places where all these intersections would happen, right? And all these elements, “This character is of this faction or is of this mindset, so they would be in conflict with this thing.” Once a game like this starts getting big or even just medium sized. Even a medium-sized RPG would have trouble with this.
Dragonborn is easily multi continental in both durability and strength as he scales higher then the greybeards that was able to shake the world with their voice alone and take all the combined greybeards shouts that have multi continental power.
From the Odes: "He was born in Atmora as Talos, 'Stormcrown' in the language of the ancient Ehlnofey, and it was from that shore he sailed. He spent his youth in Skyrim among the Nords. There he learned much from the Tongues and their chieftains and their ways of war. At twenty he led the invasion of Old Hrol'dan, taking it back from the Witchmen of High Rock and their kinsmen Soon the Greybeards made known that they were restless. Already the storms had begun from their murmurs. The Greybeards were going to Speak. The surrounding villages were abandoned as the people fled the coming blast. "The villagers warned Talos to turn back, for he was marching to the mountain where the Greybeards dwelt. "Inside he went, and on seeing him they removed their gags. When they spoke his name the World shook.
http://en.uesp.net/wiki/Lore:Pocket_Guide_to_the_Empire,_1st_Edition/Cyrodiil
This can be refuted as bieng a hyperbole but that's not the case as Todd Howard confirmed the greybeards can shake the world with their voice
Todd Howard: The greybeards, the guys who live up on the throat of the world, who are the masters of the voice, they find out about this fairly quickly, and they shout your name. They shout Dovahkiin to the wind, and it kind of rumbles through the world. The mountains shake when they call you. And you think ‘what was that,’ and someone says ‘that was the greybeards calling you. To walk the 7,000 steps up the throat of the world to meet them
It is stated by Arngeir that the last dragonborn is greater then the greybeards in the Ways the of thu'um.
But your ability to absorb the dragon souls and do the shouts on the level that you can is beyond them
https://www.gameinformer.com/b/features/archive/2011/01/20/skyrim-s-dragon-shouts.aspx
Some people might say that the greybeards were holding back but that’s not true as Arngeir directly stated that they were unleashing the power of the voice without holding back here's the evidence:
Arngeir: Few can withstand the unbridled Voice of the Greybeards. But you are ready
Some might say if the greybeards can shake the worlds in tes with their voice then why isn't there castle destroyed? That's easy to explain as tes buildings can be enchanted same as weapons allowing them to have higher durability and the greybeards castle isn't just a normal castle or else it will be destroyed by the greybeards voice here's the proof:
Realizing a need to preserve our knowledge against the ages, they excavated a cavern east of the mighty Strid. There, in its alabaster depths, they carved great halls and sealed them against the ravages of erosion and time.
They summoned our greatest architect to do these things, and a great enchantment was placed upon its walls to stave off putrefaction and decay.
Some might say that doesn't mean the greybeards area is enchanted but it is more then bieng enchanted as the greybeards castle is built on top of a metaphysical tower that is the throat of the world that is better then any simple enchantments:
The Aldmeri or Merethic Elves were singular of purpose only so long as it took them to realize that other Towers, with their own Stones, could tell different stories, each following rules inscribed by Variorum Architects. And so the Mer self-refracted, each to their own creation, the Chimer following Red-Heart, the Bosmer burgeoning Green-Sap, the Altmer erecting Crystal-Like-Law, et alia.
Aldmeris bore witness and built the remaining towers during the Merethic: White-Gold, Crystal-like-Law, Orichalc, Green-Sap, Walk-Brass, Snow Throat , and on and on, "aad semblio impera.
https://en.m.uesp.net/wiki/Lore:Aurbic_Enigma_4:_The_Elden_Tree