MAVE knew about Sonata Florin's real identity.
Celeste had also warned him in the past that he shouldn't mess with the "real heroine" because he wouldn't win a fight against her.
Even so, he wasn't able to stop his anger.
He put a spell around the diary that would inform him if another person other than Sonata Florin would touch Celeste's diary. To be precise, the spell would let him know if the diary had fallen into Diether Hexford's hands.
And it did.
Hence, Mave used a powerful spell to break through the portal's walls.
He had every intention to kill Sonata Florin.
Unfortunately for him, the woman had managed to get rid of his attacks easily.
Sonata Florin blocked his lightning bolt with her blood, and she even froze the water flowing inside the portal.
[Her blood is really frightening.]
However, right at that very moment, Mave didn't care because he was consumed by anger.