Oyakata

Whoever leads the Ubuyashiki Family holds the title of Oyakata, and the role transfers to the eldest son once the sitting leader dies. Unlike the slayers who fight demons directly, the Oyakata cannot battle because of his failing health. A hereditary curse afflicts the family with an illness that raises burns across the skin, gradually robbing them of their bodily functions and sight, and none of them lives past the age of thirty (Chapter 137).

As a result many take up the role while very young. Kagaya Ubuyashiki became leader at four after his father's death, and his son Kiriya at eight. Knowing their time is short, each leader raises their children with strict urgency so that a capable successor is ready when the inevitable comes.

Though he lacks physical strength, the Oyakata brings fairness, composure, and shrewd judgment to the Corps. Generations of these leaders have shown an uncanny ability to anticipate events and sway the feelings of those around them. Kagaya excels at this, with a charisma that can lift and inspire people through his voice and bearing alone, an ability that earns him the deep respect of every slayer. The family's intuition has also built their wealth and steered the organization through crisis.

Because of his fragile health the Oyakata stays within the Ubuyashiki Estate, overseeing daily operations and relying on Kasugai Crows to stay informed. From their reports he coordinates where slayers are deployed, supervises the Final Selection, and holds meetings with the Hashira. By tradition the Oyakata keeps no personal bodyguards despite the danger, so elaborate methods are used to hide the estate's location instead.

Around a thousand years ago a relative of the family, Muzan Kibutsuji, became the first demon, an event that set the family's curse in motion. Guided by a priest, the Ubuyashiki founded the Demon Slayer Corps and dedicated themselves to destroying Muzan in the hope of breaking that curse. Kagaya Ubuyashiki was among the last leaders, sacrificing himself by detonating the estate to trap Muzan. His son Kiriya then led the Corps through the final battles, freed the family from its curse, went on to become the oldest living person in Japan, and ultimately dissolved the Corps while doing away with the title of Oyakata altogether (Chapter 204).