She finally decided to let Pinne go. Her wings. The only thing that was keeping her "sane". The last link between Dorothy and her role as a Goddess. Now, at the end she was telling us her plan, but not the whole picture. Only her true goal, and giving us hints about the "choice" that EVERYONE will have to make. So far only us (rapi and skk) and Snow White (and probably Scarlet and Rapunzel too) know about that. But obviously only Dorothy knows the real thing.

With Pinne out of the picture, the real wingless angel was born. In other words, Dorothy fully embraced her role as Lucifer. And nothing can stop her to achieve her goal now. Not even her friends (including us).
Doban saying at the end "No one can threaten my Kingdom" is obviously a reference to God's Kingdom, and how Dorothy is planning to completely destroy Paradise.