Confession wasn't a good option after all, it actually made matters worse.
Recalling how Rurumi begun her transformation, she was driven by being jealous of Kana freedom, that could trigger her Drasil to hatch.
Drasil consumed most of Hatsuna, but magic is in Drasil and her body is just a shell for it, guess there's no way for return...
Takaya didn't even got his answer and Drasil bit a large chunk out of him, at least didn't regret to confess his feelings like he said...