Board Thread:Questions and Answers/@comment-24.62.142.87-20140331201702/@comment-6697950-20150428064533

Hey hey, please don't take my words out of context. That was said on a topic where some guy believed that the author intentionally left out material from the LN for the anime to have original content, which isn't true, since the author comes up with any original content on the spot if needed, but never actually plans anything like that in advance. I never said that he explains all the details about the game. He wouldn't have anything to write about if he had done so.

And yes, there is no specific statement that it was THE boss, just that it was a boss from the 50th floor. The assumption that it was THE boss comes from the fact that Elucidator is considered to be an overly powerful weapon for a drop.