The room was dimly lit, and two tall, stone pillars were at the front, before the altar.  Four people carried in the limp form, and they first affixed the manacles, made of high temper carbon-steel and laced with titanium.  Then the pulled the chains taut, until the sound of joints creaking was audible.  Then they began to light the candles, even as one of them inserted something into one of the veins, and dosed the unconscious one with something.

  The figures came back a couple hours later, administering another hypodermic full of something, an even larger dose, as the person hanging by their arms had begun to awaken somewhat.  Then they hooked up an IV, temporarily, using a machine to rapidly push the IV unit into the figure before they left once more, the altar at the front now covered in black silk embroidered in designs.

  Robed figures entered the room, chanting.  The preparations had been completed, and one of them went to the altar, beginning to paint sigils on it's surface with a thick red liquid that was clotting as he painted.  The sigils completed, the incantation began.
  The robed figures began to move in a complicated pattern, as the altar began to glow with a dark and ominous energy.  Black lightning began to crawl over the altar, then arced to the first of the two pillars.  The form suspended between them had begun to stir, and lifted it's head.  Unable to speak for the ball gag in it's mouth, the figure was chained, and helpless to fight effectively as the lightning slowly became more intense.
  When the first bolt struck, the muffled scream was clear.  And then a second hit, and a third.  The figure struggling, still trying to scream.  Even as a sigil chalked around it on the floor began to glow too, matching the color around the altar.  And then the whole sigil lit up, as the figure screamed.  And the earth shook, as the screaming became laughter, a deep, rumbling basso laugh that was subtly inhuman.