Lore on Ghost! Reader:
On the Wayne property, deep in the woods, there is a tree that is covered in old coins. Its by a creek creek and there's a rumor that the area is haunted by the ghost of children.
The reason the tree is covered in coins is because everytime someone who knew about Ghost reader's existence leaves the manor, they hammer a coin into the tree, a sort of goodbye gift to the spirit that watched over them during their time in the manor. The tree serves as a living memorial to all of Ghost Reader's children who have long since died and moved on.
Because the tree is a living reminder of their children, Ghost Reader is very protective of it, earning thier place as one of Gotham's oldest cryptid. Ghost Reader thinks its a bit silly, especially when teenagers sneak onto the property to see if they can 'summon' the Hellbeast of the Wayne Property, but they do think its fun to scare them.
Nothing that would give Ghost Reader away, but they will rustle some trees and bushes when there is no wind, make weird noises that could be brushed off as an animal, maybe blow some cold air against thier neck and whisper unintelligible words in the wind. Its so funny watching them getting spooked and running away, it reminds them of when they were alive and they'd scare their six younger siblings with Ghost stories before bed.
the irony is not lost on them.
Its all good and fun, something that continues to amuse Ghost Reader throughout the years. However, there are individuals that visit their tree that... frustrates Ghost Reader.
People who try to cut down their tree.
Not so long ago, back in the 30s, a small group of men discovered Ghost Reader's tree and came up with the 'brilliant' idea that if they cut it down and harvested the centuries of currency from it, they could get rich quickly.
Unfortionately for them, ghost's are possessive beings.
Especially when it comes to graves and memorials.
Ghost Reader feels a little bad about what they did, but only a little. After all, didn't their parents teach them the dangers of trespassing on someone's property? Didn't they know there are risks to tying to steal from a memorial??
Actions have consequences.
And their consequences were coming face to face the Hellbeast of the Wayne Property.
I love monster designs, with one of my favorites being the bear in Annialation.
I'm not making anything canon, but I like to imagine the monstrous form that Ghost Reader takes is similar to a bear. A large, towering body, long and powerful claws and teeth capable of snapping bones as if they were brittle twigs. However, what they change is making their body longer, thinner and sickly looking, with its stomach clinging to their 'bones', as if its starving. They also like to make their eyes appear as if they are glowing, after all, nothing scares humans more than knowing they are being watched by something they can't comprehend.
Imagine Ghost reader in that form, standing on thier hind legs and reaching a height of 12 ft tall, staring down at them, their eyes glowing and their body shifting between tangible and intangible as they let out an unnatural, animalist growl:
"Hello."
The police found two of the men hiding in storm drain the next day.
They were in shock, shaking and stare at nothing, only speaking when the police try to take them out of the storm drain.
"Please don't! Don't make me leave! I don't want to die -- please I don't want to die --!!"
A week later the third member of their group washed up in the Gotham harbor. His back sporting four long claw marks...
People started to avoid the woods around Gotham after that.
Especially the woods around the Wayne Manor.