Judas
Your name is Judas and today marks the start of your new life... if you can call it life that is. Your father was always the hands on type, always exploring new possibilites and pushing the boundaries. I suppose he's the one that got you into this mess. Today, he turned both of you into the undead.
Your father seems to be taking it pretty hard. I guess he blames himself for messing up in the lab. You knew he shouldn't have accepted that pamphlet from the friendly neighborhood satanist.
It's been three days since he's last talked. All he does is sit in his chair, hat pulled down over his now rotting eyes. You know he isn't dead though. You've spent far too long experimenting with your newfound quasi-immortality to think of that. Anything short of a silver bullet to the brains wouldn't do it.
Although you now have eternity, a six year-old's patience still won't allow any more waiting around. You decide to cheer him up. You've been left sad and alone and you need to make some new friends. Hopefully your father gets up by the time you get back.
You/Judas

Your Mentor/Father
You play as Judas, a six year-old undead. Now that your father has stopped responding to you, you decide to go out and make some new friends.
When meeting new friends, you convert them into undead so that they can enjoy all of the benefits and interact with you without screaming. Judas seeks fulfillment and happiness by expanding his own personal zombie horde.
It soon becomes a challenge to manage your resources and to continue expanding your zombie horde.
Depending on your final score, different levels of happiness are achieved. A perfect score reveals the secret ending, you father is actually dead. It was a silver bullet through the brains.... I wonder how Judas knew that would work?