The Fall Gauntlet: BEAR. The Fall Gauntlet, #1

Benji and Soren will do anything to save their family, but the Crown isn't going to make it easy ... Ten years after his mother was thrown into her off-world prison, Benji finally has a chance to save her. All he has to do is win the Fall Gauntlet, a fight-to-the-death tournament on the planet of Calypso, designed to please the gods and goddesses and keep them at bay. Benji's success will usher in a new era of science and innovation, and he's come too far to lose now.
But the Crown is three steps ahead. They've orchestrated every move, pushing Benji to the victory that will serve their own agenda. Winning the deathmatch will grant his wish to save his mother, but the Crown has other plans and won't let go of Benji so easily. As Benji learns the truth about the Crown's desires, he is forced to make impossible choices, especially when he learns that his final opponent-the hulking young man behind the bear mask-is his brother, Soren.
J. A. Merkel's Bear is part of The Fall Gauntlet, a collection of dystopian sci-fi short stories about Benji and Soren's misadventures to outsmart the Crown and save a family lost to them, all while learning how to be brothers again.