Forgiveness.

You tremble with rage, but manage to pull yourself together. The poor woman had no idea what she was doing, did she? No, she deserves forgiveness and a gift. You crouch down with a sigh, lifting Keira's chin up so you can see her teary eyes.
"Now, now." You say, that seductive vampire spell slipping into your voice. "I understand why you ran, change is scary." She has stopped crying now and only watches you inquisitively. "But change comes to us all. It will come to Sarah soon, and you now." She ponders this thought for a moment, then leans into you with a smile and a sigh.
"I'm so tired Linus." She says. "I'm so tired of being ugly and weak. Take it all away." You embrace her and kiss her hair gently.
"And so I shall, would you care to enjoy your human body one last time?" She looks up at you and nods. You lay her out on the ground, pulling her panties and skirt off as you do. You greet her pussy with a tender lick of her clit, before pulling her shirt and sweater over her head. You slide over her, teasing her entryway with the tip of your penis.
She gasps and says; "Oh I've always wanted you Linus. I was so jealous when you and Sarah started dating." She puts a hand on your face tenderly. "But I have you now."
You smile down at her and enter, Keira's tight vagina gripping your dick perfectly. She groans, arching her back as she does, and you begin to thrust. Each movement elicits a moan or a whimper, and she tosses her arms and head around, driven mad by the ecstasy. You lean in over her tiny form and bite her neck gently. This is the final straw and she yells and quivers in orgasm, but it isn't over yet. You pull back before you drain all her blood, keen for her to observe her own transformation. She looks down at her breasts as they grow into perfect, perky orbs. She massages them and moans as her canines extend into vicious blades. She grips harder with her now muscular thighs, just as her vaginal muscles strengthen and grab at your cock hungrily. You feel her ass grow in your hands, each cheek firm and round. The classic pale sheen covers her body, and finally she looks at you with glowing golden eyes.
"Ohhhh yes." She moans, her hands looping behind your neck as she sits up, her face mere inches from yours. "Fuck me harder!"
You push in and she responds in kind, her grinding against you as much as you against her. She pushes her long tongue into your mouth and you meet it with yours. She grins at you between moans, and you let forth a few grunts too. Her breasts press into your chest with each thrust. Suddenly, you both reach climax, the moan becoming a cry of pleasure. You hold her to you as you shoot cold cum into her icy body. You both convulse against each other, your tongues exploring the others mouths once again. Finally, you finish, holding Keira gently in her arms as you stand. She gracefully regains her feet and helps you wrench the fire door free from its hinges. Then, with a final goodbye kiss, she disappears into the building to find her brothers and sisters.