Thread:NewGenTV/@comment-1746153-20141030143604/@comment-1746153-20141217190858

It's not. But it's a valid translation variant. Many AgK characters (if not most) have name translations that don't match the romaji completely, and we agreed to roll with the most official source available, just like in case of Esdeath and the others who were called by their unofficial names before the guidebook was released.

Just like Lubbock is written as Rabakku in Japanese, with fan translation calling him Rabac, etc. The pronunciation is almost the same in all cases.