Desertrians emerge as recurring antagonists when the Desert Apostles steal human Heart Flowers. These stolen flowers wilt under the influence of negative human emotions—like jealousy, fear, or distress—and transform into Desertrians by merging with nearby objects. The degree of the Heart Flower's wilting directly determines a Desertrian's power: partially wilted flowers create weaker entities, while fully withered flowers generate significantly stronger ones. Summoners can accelerate the wilting process to empower these monsters and, using Dark Bracelets, fuse with a Desertrian to gain enhanced combat capabilities.

Each Desertrian's physical form and abilities manifest from the object it possesses. Consistent traits include gray surroundings framing black eyes and a basketball-like sphere on the abdomen. When fused with a Desert Apostle, Desertrians take on more menacing aspects, such as sharper contours around magenta eyes and spikes on the head or shoulders. They autonomously generate limbs as required and uniquely articulate the name of their possessed object during speech, a trait distinguishing them from earlier franchise monsters. Their object-based abilities vary—a soccer ball Desertrian excels at athletic maneuvers, while a street cleaner Desertrian manipulates debris.

Across official media, Desertrians consistently form from specific emotional crises:
- In the original series, a girl's jealousy toward her sister births a lost doll Desertrian, and a patient's surgical fears manifest as a wheelchair Desertrian.
- In the sequel *HeartCatch Pretty Cure!☆Reborn*, envy over a peer's popularity creates a makeup kit Desertrian, and obsession with uncovering secrets forms a calendar Desertrian.
- Movie-exclusive Desertrians include an obelisk born from a character's desire for freedom.

Defeating Desertrians is central to the protagonists' mission, as each victory releases Heart Seeds. These seeds rejuvenate the Heart Tree, countering the Desert Apostles' global desertification. Desertrians are eliminated by specific Pretty Cure techniques like Pink Forte Wave or Floral Power Fortissimo, with advanced forms requiring combined attacks like Heartcatch Orchestra or Shining Fortissimo.

Desertrians represent franchise firsts: they originate directly from humans rather than merely possessing inanimate objects and adopt "desert"-inspired nomenclature instead of Japanese wordplay. Their capacity to victimize civilians—including future Pretty Cures—prior to transformation further sets them apart from earlier antagonists.

In all iterations, Desertrians lack autonomous evolution or personal backstories. They serve purely as manifestations of human negativity and tools for the Desert Apostles' goal, embodying emotional conflicts the protagonists must resolve to restore balance between humanity and the Heart Tree.