The brothers belong to the noble house of Black an ancient and wealthy pure blooded wizarding family who share the dark lord’s blood supremacy beliefs. Sirius Black is the older brother he hates his family and what they stand for, he is arrogant, confident, playful and handsome. His younger brother Regulus is much the opposite, being reserved, withdrawn, cold and unreadable. Regulus has taken the dark mark representing the house of black making his brother hate him even more. 