Supposedly, Twisty.
/vt/ is claiming the Twitter handle has been hijacked by Frank, the paypiggy Twisty is talking to in the leaks and the one who sent the leaks to False. They also claim him to be Twistyschizo, a poster who both advertised and anti'd Twisty on the board frequently up until recently.
I think (fuck if I know with these schizos) the rrat they had for the past few days was that Frank is a groomer who leaked to False in an attempt to get Twisty fired on purpose to isolate her for prime grooming but failed to expect False would reach out to her to confirm the details he was given.