I say Cassandra Cain on the basis of Dragon being less active and not fighting top fighters as much in recent years as he did in his prime, but still, they're the two best, who wins is largely a matter of opinion and it's a near even match no matter how you count it.
Richard Dragon is more like the old sensei who trains and teachers. He doesn't have that many feats in recent years. He was the best mma in dc back in the day.
While Dragon may be considered on of the greats, but hearsay and the hypothetical only go so far. If DC ever decided to give him some real spot light, I have no doubt that he would at the very least be a contender for Cass, but as it stands he really doesn't have any valid feats in current DC cannon to validate a win.
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