This act of eating your own mother will send you down a dark path. (I am just writing this as a contrast to the light path option, I do not mean to continue, warning this gets bad.)
You leave the room and enter your parent's bedroom. You waste no time and swallow down your surprised further. He kicks and screams a bit but settles down when he finds himself tucked away with his naked wife. Two fully grown adults and a half digested child buldge out your gut as you return to your sister.
The baby has started crying again "What am I going to do with her?" Your sister asks.
You take the baby off your sister "Say Aarr" You instruct like your a doctor.
"Whaaaaaaaaa mmmmmmumuuum!" Your sister begins to ask but is cut off as you shove her own baby down her throat.
"She is human, and too young to convert. She means nothing now. You are mine."
"My baby, I ate my baby." Rebecca mutters in shock.
"And didn't it taste good. Doesn't it feel good squirming in your stomach?" You reply a dark grin on your face. You could feel your parent's fucking their last time inside you. You pounced at your sister. knocking her onto the bed, breaking it.
"Yes, yes it does." Your sister replies pulling you in for another round.
You feel multiple bodies squirming below you as you fuck your werewolf sister in your werewolf form. You both howl as you cum and feel the life leave your respective bellies.
Now time your sister got her first blood. The two of you leapt out the window and started a night of terror and mahem.