Dom is the son of Eduardo Santiago (a former Gear himself) and his wife Eva Santiago, Dom was born and raised in the city of Ephyra with his older brother Carlos, Dom attended Olafson Intermediate school with his brother Carlos, one day when Dom was 8 years old Carlos (who was 10) brought home his new friend home, Marcus Fenix (Carlos and Marcus where in the same class), Dom’s first impression of Marcus was that he was posh and rich so he wasn’t sure why he wanted to hang out with Carlos but he quickly came attached to him. Dom, Carlos and Marcus spent massive amounts of time together and developed a strong brotherly bond, Marcus spent most of time at the Santiago’s and he quickly became known as the third lad.
Dom was with Marcus and Carlos (they where 13 he was 11) in their backyard when Eva gave Marcus the news that his mother had gone missing, Dom thought he wouldn’t see Marcus again but he was in school the next day and he started spending even more time away from his father, Ed and Eva became second parents to Marcus and had a big hand in raising him. Dom wasn’t comfortable around Marcus’s dad, Adam Fenix who was a former gear himself but he was now a high ranking professor in the C.O.G, he was very distant and very formal even to Marcus but it always seemed that Adam wanted to say how much he loved Marcus but could never quite find the words.
When Dom was 11 he met a girl called Maria who lived on his street, they quickly became friends and started going out when they were 14 , when he was 16 he and his brother Carlos (18) joined the C.O.G and were about to start their basic training but that wasn’t the biggest thing happening in his life, he had got Maria pregnant. He talked to his dad Ed and he was expecting a punch or at least a bollocking but all he got was a pat on the shoulder and Ed told him how proud he was of him and Dom promised he’ll sort everything out, Dom’s mum was also very happy for him and Maria and told him to finish school and get a good job.
Dom proposed to Maria and she happily agreed, when asked if he was only doing it because it was the right thing to do he said that they always planned to get married sooner or later it was just going to happen sooner than expected, both Marcus and Carlos wore their C.O.G uniforms to the wedding and Eva said “I'm proud of my boys, all three of them”.