Also, just to make things fair, I'll say that the D-HERO archetype is uncommon/rare (depending on the card). I'm saying Plasma is unique, however, on account of Aster having the most trouble obtaining that specific card. Besides, most aren't even powerful until you get to the Level 7+ monsters (Dogma, Plasma, Dreadmaster [under the proper circumstances], for example). Anyway, Plasma, unlike all the rest, was infected by the "Light of Destruction", and due to this, likely non-copyable. The others would still be easily capable of duplication.

Therefore, Plasma would be the only one in need of an explanation, unless an explanation would exist as far as how an infected card could be copied without possessing half of everyone who handles it.