We already have the introduction and Bianca as recurring villain.
Middle phase: Let her reoccur from time to time but sparingly. The PCs might come across some of her schemes but generally speaking she should be a distant mover, not an imminent foe on the street. On the other hand it might be possible for the PCs to meet her on some occasions on Accorded Neutral Ground (I really do like this idea:
http://forum.rpg.net/showthread.php?517766-Dresden-Files-RPG-101-Plot-Ideas&p=15095570#post15095570 - what if one of the PCs shares some cultural tastes with a villain? Wouldn't it be funny to discover that you and your powerful vampire foe both like films by Griffith or Antonioni? I mean, vampires are cultivated monsters, aren't they? Monsters, that is... Don't forget that.) The general idea is that both sides should develop some kind of mutual respect. To some degree, of course, as the vampire war is raging. But you can skip or change this phase, it really doesn't matter much. Develop the story according to your tastes and to the response from your players. Make her as monstrous and villainesque or as trustworthy and respectable as it suits your needs. She might be even willing to cooperate on a rare occasion. (My enemy's enemy is my ... ally. For now. Sort of.) Or not. It's up to you.
Climax: Have Bianca be a part of the climatic events in
Changes. She's present to the ritual and is the only one of the Red Courts who tries to avert the imminent disaster. With "No, you ****ing retards!" screaming at the soldiers and Red Court aristocracy, she rushes toward the PCs and tries to prevent them from sacrificing Susan. She fails, of course, but as her hand touches the knife at the moment of casting the spell, she's exempt from the effect. She was efectively co-performing the ritual and such potent magic has its fail-safes (or whatever explanation comes to your mind). So in an instant the Red Court is wiped out from existence ... save for a single vampire whose world has just shattered. She's standing there still, not being able to grasp the situation, her icy eyes filled with horror for the first time. She's alone. Technically a Red Queen now but without her kingdom, stripped off everything. Had she just killed the PC outright a few years ago! But then, she played with him, with his fears, she was the cat and he was a mouse. She let him go, hoping to cripple the future actions of the White Council as one of their wizards was indebted to her "kindness". Now the hunter is the hunted and the mouse has become a sabre-toothed tiger. She's frozen, stricken with panic, for the first time in her long and bloody life she doesn't know what to do.
But the situation is interesting from the PC's point of view, too. What now? The Red Court is history but ... there is one vampire left. Given enough time she would repopulate the Earth with new scions. And the St. Giles' Order doesn't exist either. On the other hand it was this particular vampire a few years ago who, given the opprotunity to kill the PC or destroy his family, refused to do that. The PC remembers the keys to his chains, "forgotten" on the table. And the liberating sound of his girlfriend's voice after that horrible, horrible night at the theatre. And both the doctors' verdict and the verdict of the St. Giles' Order's scholars: "She hasn't been harmed in any way." The PC raises his head and the eyes of the human and the monster meet. Her eyes are not the eyes of a human being ... they are the eyes of a cornered animal...
