I have soooo many questions x'DDDDDDDDDDDDDD
SHE HAS A DARK STAR LIKE ENORMEETA MEMBERS. This transformation is definitively due to Berserker Baiser corruption. Like they have mentioned, the remanants of that corrupted magic reacted by themselves in chapter 40 and now they interrupted the La Verita transformation (as we can see in some panels, she was going to be wearing a dress just like she imagined), covered her in a black lotus and merged with her, that explaining the personality change.
DUDE, this manga is so freaking good x'DDDD ¡¿HOW CAN IT MAKE ME EXCITED WITH SUCH A CLICHÉ?!