After years in the infected island of Chernarus, having lost all friends.. and sense of humanity, he roams the military bases searching for people to make his prey. He's killed countless amounts of people at this point but he doesn't care. Garrett has avoided cannabalism so far but may soon resort to it to calm his psychopathic outbreaks. He has met people and released them, others havn't been as lucky. He used to be in a small group with two friends until one of them betrayed him and killed the other and left Garrett to die with the zombies, from then on Garrett had last all sense of empathy and sympathy.
Before the outbreak Garrett spent his times in the outdoors far from civilization with his survivor-like Uncle Lopez. In his childhood he learned how to make anything necessary to survive, and to do anything to survive. His Uncle knew one day the world would go south and he wanted Garrett prepared for it. During the outbreak he see's himself having severe mental break downs and one could even call them psychopatic outbursts with how severe they are, including attempts of suicide, and randomly becoming extremely aggresive.