Webkagaya ubuyashiki is the leader of the demon slayer corps who is held in high regard by his subordinates.
He appears to be a powerless man, but the anime has.
Webin fact, kagaya ubuyashiki—the leader of the demon slayer corps—views this victory as a portent that they’ll finally defeat muzan during this generation.
Webas part of the ubuyashiki's curse kagaya's forehead is shriveled and a pale lavender color.
It's shown that the disease was gradual and by the end of his life right before his.
Webin the finale of season 4, we saw kagaya ubuyashiki sacrifice himself to give the corps a chance to kill the demon king, once and for all.
With the final arc.
Webit turns out that kagaya ubuyashiki sacrificed himself and his family just to slow muzan down a little.
This gives tamayo the opening to attack muzan with a blood.