User blog comment:Servant of Evillious/Clockwork Lullaby Analysis/@comment-98.118.56.224-20130531083154

"it finally debuts on stage"

The line of concern here was originally それは既に舞台に登場してる

I have no idea how this line could have been translated as "it finally debuts" but my guess is that the translate confused 既に with 遂に.

The more accurate translation: it has already (not "finally") debuted on the stage.