In DMC3, a low level demon was able to break it easily
Incorrect. Moving on
I believe my argument was a very compelling "He is freaking Superman".
And superman has had his punches blocked by other mortals, really clever scientists, and even faces that were too resilient to be punched. Your assertion that "He is freaking superman" just establishes him as a character where his punches can fail if the amount of power he puts out is not enough. The established mechanic for royal guard is that no amount of strength
matters, and any attack will simply fail against a well timed block
Technically, yes.
But only if Superman let's him. Obviously if Supes throws a punch at near light speed, Dante won't be able react in time.
absolutely. In a one-on-one fight, superman would easily tear dante a new one because there's just so much bullshit written into his character, no other character really stands a chance. Traversing the width of the universe many times in a single day, reviving himself from death more than once, time travel, psychic powers, it's just too much to handle. But if we're going to narrow it down to superman landing a punch on a successfully timed royal block, then yes it would be fully blocked, because a royal block negates any amount of damage, even if it's an absurd superman-quantity of damage.
Probably. There's no way that there can't be some sort of power balance to offset that kind of protectional barrier. It's insane to think that absolutely nothing could get past RG.
it's insane to think someone could punch so hard that they rewrite the laws of the universe, but you are setting this up as acceptable, while a block that ignores any amount of damage is not? You're not being very reasonable here.
The gameplay mechanic of DMC is that if a parry is timed correctly, no matter what attack it is, no damage will be suffered. It could just be that royalguard is impervious to scrutiny because there's so little written about it that it was never assigned a flaw, but that's how it is. On the other hand, superman's punches have failed time and time again.
So instead of cherrypicking what we deem acceptable and unacceptable, I'm moving that we accept both characters at full power. Superman's punch has so much strength that the universe will split in half. Dante's block is so absolute that the amount of damage contained in an attack is not relevant to the success of the block. Boom, easy conclusion, royalguard negates the one thing superman's punch has going for it (absurd strength vs disregard for strength) and wins.
In short, if all Superman needs to get past Dante's RG is some gas, then he could just use his ice breath. Done.
Dante has no problems blocking a gas breath attack from gluttony. The thing dante is unable to royal block is breathing in poison gas, and while we could get involved in the delightful idea of superman passionately breathing cold air into dante's unguarded mouth, I think the subject here is punches