Cillian Joyce was born in a traveller family, in a large family, with many siblings. He'd often get into trouble with the neighbouring family kids. Because of his brothers, Cillian started training for bare knuckle fights, fighting his brothers, but mainly other cocky kids on the block. His uncle, Paddy Joyce was a great inspiration for Cillian who taught him everything about fighting.
When Cillian was not getting in trouble, he scammed working people for ordinary jobs, making them pay a five times higher rate, while stealing worthy items from them and reselling them. Cillian was never caught for this and it resulted in a steady flow of income, so he dropped out of school at the age of 16.
Because all the families in Ireland were defeated by Joyces, the family went to Chernarus, because they heard there were some tough families there and they needed a challenge. The family soon encountered The Dimitri's who proved to be worthy rivals for the Joyces. Cillian was not able to continue his scammer business hes started in Longford because the Chernaruskies were tougher, knew what he was up to and could do the job themselves. So, without any inflow of money, Cillian focused on fighting in hopes of becoming the best bare knuckle fighter the world has ever seen.