User blog comment:Kaido King of the Beasts/Chapter 908: Imminent, Imbalanced, Improbable Whims/@comment-3185063-20180615081043/@comment-29325824-20180615135746

That I don't know. But considering Blackbeard's a chessmaster who played the WG before, and it's highly likely that knowledge of Im's existence is Doffy's leverage (therefore suggesting it's possible that Im is not an absolute secret), not to mention Blackbeard's still mysterious past, I certainly don't think it's impossible.