Hello, everyone. I have occasionally heard people making all sorts of claims in attempts to downplay Saint Seiya, and many of such claims have been covered in plenty of excellent Blogs and Articles. However, one "argument" in particular bugs me like few others: "Atomic Destruction in Saint Seiya is not a thing / is non-canon / is inconsistent / etc.
Well, in order to show that not only is Atomic Destruction an actual thing is Saint Seiya, but that it has been a staple of the franchise since the very beginning, I am attempting to gather every single major mention / explanation of it that has appeared in every single installment of the series.
Note: If I find other statements in other installments, I'll add them here.
This is rather easy, having been a concept that was introduced during the very first chapter of the manga. In it, Eagle Marin explains to a young Seiya the principles of Cosmos and destruction during their training.
In Saint Seiya Episode G, Galarian Steiner explains (With plenty of details, I might add) to Lithos Chrysalis the mechanics of Cosmos, Atomic Destruction and the power of the Saints.
In Saint Seiya: The Lost Canvas, Libra Dohko gives Tenma some advice and explanations regarding Cosmos and destruction.
In Saintia Sho, Delphinus Mii demonstrates Atomic Destruction and Cosmos to Shoko.
In Saint Seiya Omega, Ophiuchus Shaina, much like Marin beforehand, explains that the Cosmos derives from the Big Bang and that Saints use that energy to destroy atoms. Note: I'm using the manga version cause I'm too lazy to take anime screenshots.
Saint Seiya Episode G Feat: Quantic Level Destruction
Now, if all these collected examples are yet to convince you, how about I show you some feats that outright prove that they have Atomic Destruction? Ladies an gentlemen, leave it to Episode G, the most overpowered installment of the Saint Seiya Franchise:
Pretty straightforward. Galarian had his arm surrounded by a (moving, by the way) curse made of light itself, and Aiolia used his power to break him free. As he himself stated: "The Saints' ultimate fighting technique is to destroy the atoms by burning their Cosmos. If that's the case... I should be able to destroy light itself!!!" With the context of the Saints' destructive power and the whole "Destroying light itself", I can't interpret this feat as anything but the destruction of photons. Pretty freaking impressive.
Saint Seiya Episode G Feat: Atomic Level Regeneration
Now, another question I often hear from Saint Seiya downplayers goes a little something like this: "Well, these Saints are always claiming that they atomize stuff, but no enemy has ever been atomized! They just take the punch like it's a normal attack." Well, buddy... Sadly, there is an in-universe explanation for why that is... And it's something that only ends on making Saint Seiya even more stupidly OP.
Observe this page, in Brazilian Portuguese, but with Translations of the First 7 panels by myself:
"You can become whole."
"You can bun burn your Cosmos and finish your enemy."
"How is it possible if my heart is destroyed ...? I shouldn't even be capable of moving"
"That is because they are yet to be truly destroyed."
"Remember what you mentioned about this man... About his power? That he could undo and separate the connections of every substance."
"Neither your heart, nor your right arm are yet lost. Your fangs have yet to be broken. As humans, we possess the power of the intention of transforming things, and that is what atoms do."
"May your Cosmos burn! With it, make it so that the atoms unite! With your own Cosmos you shall recover your fangs."
And here's another page, in which Aiolia actually does that:
Translation: "His heart and right arm, which have been destroyed at an atomic level... Were regenerated and rebound through his Cosmos."
So... Here you have it. The official (Episode G is canon, deal with it) in-universe explanation for why Saint Seiya characters don't one-shot each other. Through their Cosmos, they can reunite their separated atoms and even regenerate those that were destroyed. This is an insane feat, and it makes Saint Seiya a verse where pretty much every single character has incredible durability to Atomic Destruction.