Spoilers . . . . . . . . . Melissa will fight and lose to Migen, however she's the one who...

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Melissa will fight and lose to Migen, however she's the one who's going to defeat him.

Yona is going to use a device to block Migen's magic. Him and Melissa are going to fight hand to hand combat, and he is clearly superior to Melissa and he's going to beat her up.

Up until then, Nine will not interfere because he understands he has to protect Yona because she's the one blocking Migen's magic.

However Migen is going to eventually overpower Melissa and he's going to bite her,and she will be unconscious. That's when nines werewolf blood will awaken, instead of Jack's: he realizes that the only person capable of saving Melissa is Yuri, who is trapped by Migen's magic, and thus he has to defeat Migen to release her if he wants to save Melissa.

But the fight was already won because Yona's device had a time limit and, after the time limit was over, Migen still couldn't use his magic. It is revealed then that Melissa used the opportunity to stab him with her sword, when Migen bit her, and since her sword is magic it cancels werewolf magic.

So Nine beats him up and the last thing I read was that Nine had fucked him up, and recognized that it was only possible because Melissa had hurt him with the sword.

And I really love that because it's consistent with the plot that Melissa is the heroine, so it's only coherent that she's the one who defeated Migen. She wasn't suddenly weakened down for the sake of ML protagonism. She fought bravely to the end, and Nine finished the job as part of his development. But SHE was the protagonist.