Mario Casas, has 4 siblings. Born in La Coruña, although very young, at just 4 years old, he left with his family to Barcelona. Later, at the age of 18, he emigrated to the Spanish capital in an adventure in which he took his whole family with him. His parents were very young when they had him; his mother, Heidi, was only 17 and his father, Ramon, 19. Only a year and a half later they had their sister, so they were very young and had two children. For Mario, his father is his reference, while his mother, like his brothers, are his confidants. His mother has been raising her children, while his father is a cabinetmaker, but has also done construction and renovation work. Because of this work, his father had no problems moving to another city, so they decided to accompany Mario when he left for Madrid and settled with him in the city. Mario has four other brothers and sisters, forming what he defines as a Sicilian family, a family with many children established around a matriarch. Mario, is the oldest of them all. He is followed by his sister Sheila, and two other brothers, named Christian and Oscar. Finally, the youngest member of the family, Daniel, who was born in 2014, and whom he considers almost as his nephew because of the enormous age difference.