The Light Is The Darkness By Laird Barron

Book Worth Reading:

Conrad Navarro is a champion of the Pageant, a gruesome modern day gladiatorial exhibition held in secret arenas across the globe. Indentured by a cabal of ultra-rich patrons, his world is one of blood and mayhem, an existence where savagery reigns supreme while mercy leads to annihilation.
Conrad's sister has vanished while traveling in Mexico. Imogene, a decorated special agent for the FBI, was hot on the trail of a legendary scientist whose vile eugenics experiments landed him on an international most-wanted list. Imogene left behind a sequence of bizarre clues that indicate she uncovered evidence of a Byzantine occult conspiracy against civilization itself -- a threat so vast and terrible, its ultimate fruition would herald an event more inimical to all terrestrial life than mere extinction.
Now, Conrad is on the hunt, searching for his missing sister while malign forces seek to manipulate and destroy him by turns. It is an odyssey that will send this man of war from the lush jungles of South America, to the debauched court of an Aegean Prince, to the blasted moonscape of the American desert as he becomes inexorably enmeshed within a web of primordial evil that stretches back unto prehistory. All the while struggling to maintain a vestige of humanity; for Conrad has gazed into an abyss where the light is the darkness, and he has begun the metamorphosis into something more than human.
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