This article concerns the A Simple Twist Of Fate version of Julius Black; you may be looking for other canon and fanon versions.
Julius Black (b. 2 September, 1979) was a pure-blood wizard, the only child and son of Regulus Black and Regina Malfoy. He was the grandson of Walburga and Orion Black, nephew of Sirius Black and heir to the Most Noble and Ancient House of Black.
Julius is described as a "tall, well-built, darkly handsome boy with fair skin, grey eyes and long, lustrous curly shoulder length brown hair that tumbled to his shoulders" and an air of "casual elegance". This vestige of aristocratic beauty is an attribute passed down through the Black Family, especially his father.