(finally realises what “Fused Prototype D” was)
Guardian Dragon’s rebirth in Saga was just too cool for words and sent shivers down my spine. But I think Atolm is the coolest and baddest dragon by far. Other than Lagi. ^.~
I think I first saw the Guardian Dragon in Saga, so I can’t really say that its reappearance was spectacular to me - but I think it would have been, had I played the games in the correct order! 
Empire ship go BOOM!! 
I think that the Guardian Dragon had the most effect on me, since I played Zwei first.
I also think it could beat the others, as long as it was in its complete form. Or maybe Altom with his massive laser thingy attached.
Hmm well done for bringing this up, I never really thought about it before…
Lets see…the Guardian Dragon would certainly be the first to go, although he would weaken the other two to some degree.
Then it would be between Atolm and the Dark Dragon…
If Atolm went all out, orbs and all, then I’d be siding with him. The Dark dragon might be kick-ass but I think I’m sticking with Atolm ^^