I like the idea, darkness in legend and form has always had a reputation from leading and twisting from the shadows.
Some things to look at.
Puppeteer is the main card here, so it should be the subject of the post.
Card search and draw is currently a very complex effort to implement and is a reason why it currently does not exist in the game. You should consider changing the puppeteers ability to simply create a Marionette in hand.
A one puppeteer limit per game is very hard to code and the reasoning seems to be to control the attack power effect of the marionettes. This could be fixed to simply give the puppeteer a nightfall effect that only hits marionettes. Something like “Marionettes gain Puppeteers Attack”
How I’d redo this idea, is make the Player the puppeteer, and the puppeteer itself a permanent and the number of marionettes you can have in play at any one time limited by the amount of puppeteer cards by only allowing the ability to trigger if you have less puppets. The puppeteers would stack and each marionette have force equal to the puppeteer stack.
The Marionnette would be great for card tricks like nightmare and mutations.