Hollow Deep Dive System

Phaethon's HDD System (Hollow Deep Dive System) is a reliable intelligent tool capable of overcoming the challenge of real-time communication both inside and outside the Hollows.
With the HDD System, project your consciousness into the Bangboo Eous and embark on the work of a Proxy!

Known in full as the "Hollow Deep Dive System," it was initially proposed by Arche, and developed by the Helios Academy with technical support from the Marcel Group. Professor Carole was the lead researcher. The core components of the HDD currently in our video store were salvaged from the Helios Academy when the old capital fell — a legacy passed down from the Helios Academy.
The HDD system aimed to overcome the challenge of observing Hollows from the outside. After substantial investment of resources and manpower, researchers finally discovered a special signal capable of penetrating the Hollow barrier. Because the signal exhibits intense Ether interference upon exiting a Hollow, it must be restored to a readable form within a simulated Hollow—like environment at the receiving end. Further research revealed that the human body was the optimal medium for simulating this Hollow environment.
The smart crystalline lens implanted in us siblings acts as a modem for Hollow data, connecting to our brains and enabling them to simulate Hollows. Even as the best-suited hosts, receiving such powerful Hollow signals strains both our cerebral and physical systems. And since the HDD draws heavily on our physiological energy, our aptitude for Ether has been compromised, forcing us to rely on Eous to explore Hollows, as it houses the HDD system's adaptation and conduction devices.
Beyond communication capabilities, the HDD also integrates Hollow data storage and computation functions. Although a hacker attack damaged much of our locally stored Hollow data on the HDD, Fairy's arrival helped us implement cloud storage for Hollow data.
Later, we learned from Mayor Mayflower that Professor Carole had been researching ways to reduce the HDD's power consumption on the human body. Using the professor's remaining documents, the mayor helped us optimize and upgrade the HDD, allowing us to now enter Hollows directly without relying on Eous.
Yet regarding both the secrets behind the HDD and those surrounding ourselves, we still know very little.