A narrator always gets to know the reader before spilling their deepest secret.
I am a murderer.
She was just a silly nothing of a girl until I made her rise to fame. A pennything.
So, reader: sit down, cozy up. I'd offer a cup of tea, but you may worry it's poisoned, and you may be correct.
But I can't just tell you how she died. That's too easy. Too quick. Buckle up: you're in for a villainous monologue.