The Power of Taboo
S3, E13: Kurama places his soul on the line and issues a challenge to Kaitou: one by one, the letters of the alphabet will become taboo. If any of the taboo sounds are uttered, the speaker will face a terrible penalty.

S3, E13: Kurama places his soul on the line and issues a challenge to Kaitou: one by one, the letters of the alphabet will become taboo. If any of the taboo sounds are uttered, the speaker will face a terrible penalty.