As Chancellor of Avalor, Duke Esteban is very knowledgeable of The Kingdom of Avalor and, as he himself boasts, knows "anyone who's anyone in Avalor". He is also a firm adherent to etiquette. He is shown to also be both shameless and a bigot. Because of this, he can be snooty and is not liked much.
He thinks his cousin Elena is too young to bear the responsibilities that come with ruling a kingdom and disapproves of her personal approach to leadership to the point where he constantly seeks to become the power behind the throne by undermining her and hates being reminded that she is the one in charge. He also wants Elena and Isabel to behave properly for their stations, likely so that they will be easily able to do what is expected of them.
Unlike Elena, he is happy to delegate responsibilities to others and simply give orders from the sidelines. Despite his differences with Elena, he does care about her enough to want to keep her safe. He seems to value his family quite enough, as he appears relieved when Isabel returns in the first episode
Duke Esteban, in comparison to the majority of the other characters, is the tallest and has a rather slender physique. He has short, slicked dark brown hair that is slightly greying around his temples with wavy side bangs that fall just above his ear. His eyes appear to be a warm, hazlenut or amber color. Although he appears in his early 30's, it is stated that he's in his fifties and was able to keep his youthful appearance thanks to exfoliation.
He is commonly portrayed in a wine coat with yellow and black accents, a yellow and blue sash, yellow neckerchief, (possibly) blue dress shirt, white trousers, and black boots.
Duke Esteban will appear in the upcoming special, Elena and the Secret of Avalor. It is unknown how he survived Shuriki's purge but he will be there when Elena defeats Shuriki and liberates the Kingdom of Avalor.
As Chancellor of Avalor, Esteban is a major character in the show that is the sequel to the special. He is a member of the Grand Council of Avalor, alongside Luisa, Naomi, and Francisco. He was chosen by the Elena for his extensive knowledge of the Kingdom and his management of it in her absence. Unlike his cousins, he is very knowledgeable of how much Avalor has changed during the Royal Family's imprisonment.