Subtle foley sounds—like room noise or outdoor ambiance—are layered into his drums to give them a "haunted" or "aged" feel. Where to Find Quadeca Inspired Kits
For the "Vanisher" or "IDMTHY" era sounds, look for libraries from Cymatics or specific feedback sound libraries like those by Akihiko Matsumoto. Sound Design Techniques for Quadeca Drums quadeca drum kit