Oculama

Lizzy appears at first glance to be a cheerful and friendly child, full of unconditional enthusiasm and kindness for anyone who she meets. This is... not exactly false, but it is not the whole truth.
In the town nestled in the forest she has made her home there is a story about a mysterious and hungry thing that eats anyone who is unfortunate enough to wander those woods after dark. This is also not the whole truth.
The smiling child in the tattered dress is the hungry thing with teeth that tear and claws that catch. Most monsters that were once human think of their humanity and their monstrosity as in constant conflict. In some, the monster wins, in some, the human. Few of these have been monsters for quite as long as Lizzie.
Lizzie thinks she can remember when her and her hunger were still fighting like that. That wasn't fun for anyone. Much better now that they get along. This way the child gets to make friends and the monster gets to have food. What does it matter if they're the same people?
She makes it quick. She makes it painless. They die with a friend by their side. They were gonna die so soon anyway. This way they die helping a friend. This way they die happy.
Lizzie does not like people or monsters that take joy in causing their victims pain.
Lizzie does not think of herself as better or worse than her friends. After all, they can die. Dying seems nice sometimes, but it doesn't seem like a thing that Lizzie can do. Besides, living is pretty nice too. There's all kindsa stuff you can't do when you're dead. You can't be happy, you can't climb trees, you can't make friends. You can't do anything at all.
Lizzie used to get really upset about the fact that she was a monster. She doesn't anymore. Life's too short to sit around feeling sorry for yourself. Or in Lizzies case, it's far too long to.