King Byogen stands as the primary antagonist in the Healin' Good Pretty Cure series. His origins stem from a conflict with Queen Teatinu of the Healing Garden. Though he defeated her Cure partner, he failed to defeat Teatinu herself, resulting in severe injuries to the queen and the infection of most of the Healing Garden. This conflict cost him his physical body, forcing him to exist as a disembodied entity seeking revival. Initially appearing as red matter with yellow eyes and a purple mouth, his form evolved after partial restoration into a black bird-like creature. This form featured large ears, a single red forehead horn, neon green eyes with red markings, long silvery-white hair and tail, a deep red cloak with a furry blue collar, a black-and-gold stole, and visible bird-like feet with red talons. His ultimate form, Neo King Byogen, emerged after absorbing his general Daruizen. This towering humanoid possessed multiple horns, pink-tipped hair, a long red coat over a purple robe, a blue-and-green stole, and two pairs of black wings. Driven by an intense desire to regain full power and conquer both the Healing Garden and Earth, he exhibits a ruthless, power-hungry personality. He views his generals—Daruizen, Shindoine, Guaiwaru, and Batetemoda—as expendable tools, exploiting their absorption of Mega Parts to accelerate his revival. Shindoine alone is spared due to her unwavering loyalty. His actions are fueled by hatred for Queen Teatinu, with her defeat his sole objective. Throughout the series, he orchestrates the spread of infections via Megabyogens across Earth to rebuild his body. He first confronts the Cures directly after they enter the Byogen Kingdom, displaying particular interest in Cure Earth due to her resemblance to Teatinu's ancient partner. Though initially overpowered and seemingly defeated by the Cures' combined Final Healin' Good Shower attack, this loss was part of his plan; he anticipated General Guaiwaru's betrayal and used the Mega Parts absorbed by his generals to hasten his resurrection. Returning to Earth, he absorbed Daruizen to become Neo King Byogen. In this enhanced form, he easily overpowered the Cures and initiated a massive infection of Sukoyaka City. Queen Teatinu intervened, trapping him in an energy cage to contain the infection, though he eventually broke free. His final act involved infecting the entire planet and absorbing the Cures and Healing Animals into his body. He was ultimately purified and defeated through the combined efforts of the Cures and the collective hope of Sukoyaka City's citizens. His abilities include firing barrages of purple lasers, summoning shadowy copies of his former body for combat, and rapidly infecting vast areas. As Neo King Byogen, he gains the capacity to fire dark red projectiles and deploy an invisible barrier that nullifies incoming attacks.