silver
They say that there are certain metals imbued with magical properties; metals that allow you to kill monsters.
She has always loved metals, with their hard, rough edges until they are tempered by fire, and then they become smooth and sharp and weapons capable of killing. Like swords.
Her fingers run along the sharp blades and she feels a rush of excitement, somehow, watching as her finger is sliced open and red fluid (her blood) drops onto the cold, pressed steel, lingering on the surface like a blemish only for a second before it is swallowed up.
Of all the metals in existence, silver probably has the most supernatural connotations associated with it. Silver kills werewolves and is recommended for crucifixes made to keep out vampires. Silver is a holy metal, a blessed metal which not even gold can hope to compare with. Bronze is too dull and gold is too gaudy, but silver is just right. Silver is the color of a star, of supernovae in its purest form, of the moon, and of the monsters that slither and crawl all around her.
Yes, silver is something powerful.
But, like all powerful things, silver can be corrupted, as metal can be corrupted by rust and turned from a bright and shiny dagger into a tarnished, flaking old thing.
She fingers the crucifix around her neck, inside which lies a bottle of holy water. Neither of them are of any use, but she likes them just the same. Just like she has a fondness for silver.
Because they are placebos, meant only to offer comfort without providing any real solutions. Placebos are good for her. She wants to feel safe even if she isn't, wants to feel alive although she might already be dead.
Underneath her, she feels the monsters squirming through miles of craggy soil and rock and feels them coming closer, until they are right beneath her legs in a storm of gnashing teeth and tongues and rusty eyes, encrusted with dirt and ore and all manner of things. They will bite into her soft, silky flesh and they will tear into her tendons and muscles and skin and corrupt her, as well; the rain has fallen, and the rust will only begin to spread, untended.
Then, she will hold out her crucifix and it will do nothing, because monsters made of steel cannot be killed by steel.
Especially not silver.