De-Aged
Shrunken; Fountain of Youth

Professional educator and disciplinarian Ninomiya Hinako is a publicly visible example of someone who normally appears to be far younger than the adult woman she is on the inside.
 Characters who were De-Aged are those metas who retain a neurodevelopmental maturity and intellect, training, and other abilities at a degree in excess of their physical age and outward appearance of maturity. In spite of what the name may suggest, this category includes not only those who were reversed in apparent age, but also characters who were frozen at an outward appearance of a younger age than their actual lived experience.

Known causes of de-aging include the mushroom Tricholoma fumetsu and its derivative compound APTX 4869, magical effects such as the Jusenkyo spring Tóngzǐnìquán, and fluctuations of the timestream and/or Speed Force. The forbidden martial arts technique 'Happōgoensatsu' may temporarily reverse this effect by allowing the user to drain the fighting spirit of an aggressive target, other known cures are dependent upon the specific cause.
Notable Users: Armijo Nena / Babe in Arms
Hibiki Ryōga (T. fumetsu, cured)
Kudō Shin'ichi / Edogawa Conan (APTX 4869)
Miyano Shiho / Haibara Ai (APTX 4869)
Ninomiya Hinako
Saotome Ranma (T. fumetsu, cured)
Sera Mary (APTX 4869)