Kai Lee Swagger was born in London, England to a struggling family. His childhood was very limited due to his family's financial situations which resulted in him having very little opportunities. He kept his head down in school and studied as best as he could to try and get somewhere in life. He had a plan and was determined to stick to it. This plan was to enlist into the military and experience active combat. He completed his secondary school education and completed the enlistment process for the British Royal Marines. He began training and excelled in the activities. He eventually passed the training phase and was enlisted into a regiment. He then saw active combat in 2015 where he was deployed as a Marksman in Kandahar, Afghanistan. He excelled as a marksman and was eventually noticed by the British SAS where he was told to apply and try the SAS selection. He applied and attempted the selection process and went on to be one of 10 people to pass and enter into a unit.
A few years into his service and he took leave from the service to go exploring around the world with the money he had saved. He explored most of the European countries before exploring the Balkans and then onto Chernarus. He went there with his brother and they explored around Novigrad before heading on to Miroslavl. They both eventually ended up travelling to the South Zagoria province when the outbreak occurred. He and his brother had to survive by any means and Kai planned on using his extensive training to help do this.