It Started with Twelve

"Has everything been prepared? Do we have the subjects?"
"Yes sir. Their memories have been altered and we are ready to start. We collected six males and six females."
The two male voices echoed through the empty area, a large white room with nothing but a pedestal in the center.
"Good, good. The arena has been cleared from the last test? The Terror's have been caged?"
"Yes sir. The bodies have been cleared, although some were missing limbs. We couldn't find them." This voice was slightly more high pitched that the other, and it held a more clipped way of speaking than the deeper and smoother voice of the other man. The deeper voiced man hesitated before speaking in a disdainful tone. "Fine. It'll have to do. Hopefully, they won't find the body parts. Now, we should go. The doors will open soon."
"Yes sir."

Trial One of Three.
The Survival.
Out of twelve people, only six can be left standing.