Koyo was born on the hard streets of Ronto where he was bullied by gangs. He eventually decided to fight back after finding a book of old medicine and some scalpels. Learning about the human body he disemboweled his enemies with precision and bathed in their blood. He would kidnap raiders from their bases and kill them in other brutal ways and litter their remains around the camps as a warning. He eventually left Ronto and continued his murderous rampage. But despite the carnage, he learned how to fix up wounds by reading the books. He eventually came across a lone ranger and a synth on the side of a road fighting a pack of raiders and helped them out when the Ranger was bleeding out.