Maria Deluca is a human who lives in Roswell, New Mexico with her single mother Amy Deluca. Her parents broke up when she was a little girl around the same time her dog died. She is somewhat kooky and high-strung with sarcastic humour. Her sarcastic humor and high-strung tendencies lighten up the often-somber mood of the show. She works at the Crashdown as a waitress and her best friends are Liz Parker and Alex Whitman. She is never shown to be particularly intelligent, unlike Liz, but she always comes through for the group. She also has great vocal talent and almost gets a record deal but she refuses it. Maria also is kind and compassionate, as she demonstrated in the first few episodes of the season, when she chose not to tell Sheriff Valenti the truth about Max, Michael, and Isabel despite how nervous she was about them.

Maria, the daughter of single mother, Amy DeLuca, is high-strung, quirky and sarcastic. Although she does not particularly excel in academic subjects, she is shown to be a very talented musician and interested in photography. She is a fiercely loyal friend, confident and compassionate. Although the person who perhaps struggles most with the alien's secret, she is also shown to keep very cool under pressure, as demonstrated in 'The Balance' and 'Wipeout'. Negative personality traits include being demanding and jealous - which is most showcased through her relationship with Michael. However, she is a very passionate person who finds it easy to open up.

In a previous existence, Max was Zan - King of a planet named Antar. After his death, his people were able to use his DNA to create 2 sets of alien hybrids 'clones' of Zan and the rest of the Royal Four of Antar. These included Isabel Evans Ramirez (Vilandra, Zan's sister), Michael Guerin (Rath, Vilandra's husband and Zan's second-in command), and Tess Harding (Ava, Zan's wife). The clones were sent to Earth to hide them from Max's enemy - Kivar.

The craft carrying Max, Isabel, Michael, and Tess crashes in Roswell, New Mexico in 1947 (an overt reference to the Roswell UFO incident). In the series, the Army finds the alien pods and takes them into a base for study. The four are saved from this fate by an Air Force pilot and stashed in a new ship hidden in a rock formation. About 40 years pass before the clones "hatch" in 1989. Max, Isabel, and Michael leave the pod together, looking like small human children aged about 6 years old. The three characters were blank slates with no memories of life on Antar, nor of the fourth hybrid - Tess (who is individually rescued by an Antarian with an agenda). It is not revealed what the characters DO know at this point, including the most rudimentary abilities - like speech - or how they would have learned them. Max and Isabella are found together by a couple of lawyers, the Evans, who adopt the two and make a loving and stable home for them. Michael hides when this happens, and is eventually discovered and eventually placed with an abusive Foster father.

Max's personality is introverted, which can be misinterpreted as shy. A theme of the series is how the hybrids must keep a low-profile to protect their secret, which often means hiding their 'true selves'. Even before he knew that he was the clone of the king of Antar, Max emerged as the de facto leader among his friends. Portrayed as the 'deep thinker' of the group, Max is nevertheless shown spurred to bold action by his protective nature, both of the other alien-human hybrids and of other people he cares about. This sometimes manifests as a character flaw, as his protective nature leads him to make far too conservative and subsequently disadvantageous choices. Along the same lines, Max hates the unknown. However, fitting into the archetypal leader role, he always takes responsibility for his actions and choices, and is never beyond offering apologies to those he hurts. Max also stands out in the group because of his unique healing powers.

A premise of Max's character is that he's been in love with Liz Parker since the first time he saw her at school when he was just six years old (shortly after emerging from the pod). He keeps himself at a distance from Liz, primarily because of his concerns about being an alien.