Name: Piers Anthonys' SOS the Rope
Author: Piers Anthony
ISBN: 9781601251947

Wandering tribes of primitive humans meet and fight and love and die. When one tribe meets another, individuals fight inside a Battle Circle. The loser must become a member of the victorious tribe. Each warrior is named by his weapon. When Sol the Sword is bested by Sol of All Weapons, he loses his tribe, his name, and his weapon. Re-named Sos the Rope, he joins with Sol of All Weapons to try to create something greater than a world of Battle Circles.
An early classic from Piers Anthony, creator of the legendary Xanth series, Sos the Rope was nominated for the prestigious Hugo Award.