The Ebon Dragon is a cruel, pathetic, hedonistic coward. Which is to say, his Virtues are badly withered to the point of being utterly crippled. He lacks a transcendental alternative, however. He can't say "Virtue doesn't matter" because it's poisonous to him and therefore not ignorable.
All the other Yozis play with extremes of Virtue. The Dragon plays with extremes of Virtue's lack. It is the Abyssals who learn to set aside Virtues as completely irrelevant to their worldview. Does that make sense?
No. The Dragon lives in a universe as a creature of sin in a world where his creation defines what is sin. He doesn't get to come up with an alternative to morality. It's not hard to guess the Dragon's Virtue ratings. To the degree that he has Charms which let him compensate for being pathetic in cheating ways, that's cool and all, but he never gets to escape that he is defined by someone else's paradigm.
Let me try again. She Who Lives In Her Name has massive Virtues. She applies them in a cosmic context, greater goods and so forth. Her Virtue is scary because it's so alien in the ways it is extreme.
The Sun shows another route to take that supasses human experience of the Virtues.
Oh, and back to Yozis, you've got Adorjan, who redefines her sense of Compassion at the very least into something quite murderous.
Having high Virtue ratings means they have a hold on you. They define your behavior. If the Dragon had high ratings, that would mean he was either virtuous in a conventional sense or had defined his own sense of morality, which he hasn't. The Dragon is defined by the sun. So if the Sun says "I'm super-virtuous, check me out" and also looks at his maker to say "You're the definition of evil and wicked and vile within my worldview," then the Ebon Dragon is going to be rated according to that worldview.
Basically, alone among the Yozis, the Dragon doesn't get to say what's right and wrong. He just gets to be someone else's conception of wrong with the added blessing that this is exactly what he wants to be.