Arena of Bloodlust

From the introduction: A subterranian battle arena has been created by a mysterious cult in order to sate the bloodlust of an otherworldly being. Those victorious few surviors of the gauntlet are to be rewarded with a grand prize. Instead, they are sacrificed to the being so that it might feed upon their prowess and grow ever stronger. The cultists are rewarded for their offerings and work to extend their sphere of influence.