Whoa, official art? That's awesome! I've always wondered though, was it ever confirmed that the black beast was a huge monster or was it always Ragna-like size? I'm sure it's mentioned in a Teach me Litchi-sensei episode....
Actually, it was confirmed to be a huge beast. At most you get headshots and the like though, but its head alone is larger than Tager. There are some alternate arcs that show it.. I believe one in Arakune's story, one in Tager's, and one in Noel's. I could be wrong though, it's been a while since I've gone through each of the stories.
The Black Beast is giant multi-headed snake thing. This is Ragna turning into an incomplete, humanoid Black Beast due to overusing the Azure in his Normal Ending.
