Like many blue roans, she has white hairs mixed with black hairs on her coat, and also has a tinge of blue in it. Her eye color is not mentioned, but most likely it would be either brown or black. She is almost as large as a full grown horse based on her age. Azul is two years old, a half grown filly, a bit older than Estrella
Stepbrother: Deceased colt
Azul is extremely cocky, cunning, and indeed very vain. She picked on Estrella, gossiped about her, doubted her, and tried to "over throw" her. She tried to influence the others that young Estrella could not lead, but bring them to their death. The Dawn Horse, or First Horse, was just a dream or made up thing from Estrella to Azul.