The Votans are not a single species, but a collection of seven different alien species who evolved on separate planets in the Votan star system. The different races banded together to flee their star system when their sun went nova, and ultimately arrived at Earth.
- One of the more prominent races in the series, the Castithan appear very similar to humans. Their coloration is very pale, however, verging on albinism, with pale white skin, white hair, and pale yellow eyes. The Castithans used to have a patriarchal, rigidly segregated caste-based society on their home planet, though this has broken down somewhat among the survivors on Earth due to the harsh conditions of the war and its aftermath. Datak Tarr, co-founder of Defiance (in the former location of St. Louis) is a Castithan, from one of the lower castes. His wife, Stahma Tarr, is from one of the Castithan higher castes. As a member of the lower castes, Datak possesses more egalitarian values, striving to work with other races through sharing of power to achieve mutual defense. As a member of the higher castes which benefited from the old patriarchical hierarchy, Stahma feels that their family should acquire more power for itself. However, this very ideology insists that it is not a woman's place to seize power, thus Stahma is faced with goading Datak into taking more aggressive measures so that he (and by extension, she) will possess more power. The Castithan language is created by linguist David J. Peterson, developer of the Dothraki language used in Game of Thrones.
- the most technologically advanced Votan race. They have bright white skin and no visible hair follicles. Their heads are hairless and smooth; their external ears don't really protrude, smoothly merging with the rest of the head. They have hexagonal shaped irises, and their skin is covered in faint hexagon-shaped scales; even their written language is based on hexagon shapes. As the most scientifically advanced Votan race, they have been upgraded with numerous genetic and cybernetic implants (which are often not externally visible). Culturally, they tend to be technical geniuses and intellectuals.
- A near-human race with an affinity for nature and adept at tribal warfare, described as almost feral marauders. Their coloration is more similar to humans than the pale Castithans, with brightly colored hair and white markings on their faces (which might be cultural decoration, not biological). However, the proportions of their facial features and slightly different from humans (and the human-like Castithans), with a wider bridge of the nose arcing towards the eyes, and very large multi-colored irises.
- slightly shorter than humans, they have with blockier facial features. They have long scruffy yellow hair. They are described as a servant-class race. Their language includes a high frequency of slang terms.
- slightly larger and taller than humans, they basically resemble a more humanoid orangutan. Their bodies are covered in reddish-brown fur, except on their faces, which have grayish skin. Their jaws protrude further forward than on humans, like apes (actors playing Sensoth characters have remote-controlled prosthetic appliances attached to their heads to achieve this effect).
An eighth Votan race did exist, but are believed to have died out when the Votan star system was destroyed, either because they were still trapped on their home planet or because they didn't survive the journey to Earth.