Unohana's Bankai comes from Bleach, the long-running manga and anime series where Retsu Unohana, captain of the Fourth Division, is revealed to be one of Soul Society's most lethal fighters. Her Bankai reveal became a standout moment for fans because it overturned her gentle healer image, and clips of the sound spread through anime edits and reaction videos. It remains popular because that reversal still surprises new viewers, and it sits naturally alongside other dramatic anime power-up sounds such as Mangekyo Sharingan in fan-made montages.