Basileus's Machine, as described by Kalina, is a house-like machine "designed by the Devil and powered by the dead". It physically resembles a two-story mansion with walls made of ectobar glass etched with Latin containment spells; at the heart of the house is a central core of huge, mechanical gears and a rotating crest of rings. It requires thirteen earth-bound spirits, all of which represent The Black Zodiac in order to work. Once the machine is activated, it will supposedly open the Ocularis Infernum (Latin for "The Eye of Hell") which grants the user unfathomable power.
The machine is named after the 15th century astrologer Basileus, who created the blueprints for the machine in The Arcanum while he was under demonic possession. The machine was built by Cyrus Kriticos nearly 600 years later. However, it was destroyed before it could gain the thirteenth ghost needed to complete the Black Zodiac and open the Ocularis.
The machine was built to resemble a big, clock-like construct, entirely made of sound-proof, ectobar glass and iron, some of the electrical wires are still visible from the outside, so as its two upper floors (above the basement). The glass panels that form the house all have protection spells to prevent the imprisoned ghosts from escaping or traveling to places others go to. Some important parts are the machine's center (where the ghosts feed the machine their life energy in order to open the Eye of Hell), the fully-protected library, and especially the basement, made of containment cubes that hold the ghosts as prisoners until the machine is activated.
Connection with the Black Zodiac
The machine was designed to use the ghosts of the Black Zodiac to open the Eye of Hell, and works when thirteen earth-bound souls, twelve of which each represent a sign of the Black Zodiac are fed to the machine's core, sucking their energy.
The main doors into the house are activated by a key inserted into a slot like a credit card.
The machine is activated by a pedal-like switch in the room which holds the machine's core. Once the machine is activated, it will automatically seal all possible ways out of the house and release the captive ghosts from their containment cubes one by one.
Once all of the ghosts have been released, a tape recording of a Latin chant is used to draw all the ghosts to the machine's core, where each one feeds their life energy to the machine. Once the machine has been fully powered up by all thirteen ghosts, it will open the Ocularis Infernum.
It is also shown that using the controls at the machine's core to reopen the house's exits when the machine is active will cause it to malfunction and explode; and that the rotating crest of rings at the machine's core will, when this happens, protect anyone inside.
It's not shown just how Cyrus moved the cubes into the basement. Certainly, there must have been some exterior loading bay that would have been used to lower the cubes underground and transport them underground to be installed and connected to the house.
It's also unrevealed as to how Cyrus built this structure without attracting public attention.