They should add this to Crow description : "at first he is supposed to be the final boss of Dark Signer arc, but since his deck make a lot of money we later turn him into protagonist"
I noticed before, it's a bit odd when the dragon mark goes from 5 to 6. Just that I never knew what's behind it.
Also another thing that I personally felt weird is, yusei mark changed from tail to head and crow get tail instead.
Like it is proposing the head mark indicates the leader of the group...haha
It actually makes a lot of sense if you retroactively look at the first episodes that mention the signers and the crimson dragon. Because the 5 Dragon Cards that are shown at some point during a flashback do not include Black Winged Dragon, BUT already included Life Stream Dragon, which didnt get used until the very end of the 5Ds anime itself.